INAF Osservatorio Astrofisico di Catania Annual Report 2002

Transcript

INAF
Osservatorio Astrofisico
di Catania
Annual Report 2002
May 16 2003
INAF - Osservatorio Astrofisico di Catania
Cittá Universitaria
Via Santa Sofia 78
I-95123 Catania (Ct)
Phone +39 095 7332111 / Fax +39 095 330592
URL http://woac.ct.astro.it/
“Mario Girolamo Fracastoro” Mountain Station
Contrada Serra la Nave (Mt. Etna)
Ragalna (Ct)
Altitude: 1725 m; Longitude: +14o 58.40 ; Latitude +37o 41.50
Phone +39 095 911580
Edited by A.F. Lanza and G. Leto
Printed: May 16 2003
Cover: Catania Astrophysical Observatory main building
Contents
Foreword
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Osservatorio Astrofisico di Catania: Staff directory 2002
1 Report OACt 2002 Summary/Highlight
2 Research
2.1 Solar Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.1 Systematic patrol of photospheric and chromospheric activity . . .
2.1.2 Solar wind and coronal mass ejections . . . . . . . . . . . . . . . .
2.1.3 Spectroscopic diagnostic and modelling of coronal structures . . . .
2.1.4 Highly energetic transient events in the solar atmosphere . . . . . .
2.1.5 Emergence and evolution of solar active regions . . . . . . . . . . .
2.1.6 Sunspots rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.7 Internal structure and dynamics . . . . . . . . . . . . . . . . . . . .
2.1.8 Dynamo theory of solar activity . . . . . . . . . . . . . . . . . . . .
2.1.9 The 3rd Italian Solar Research Meeting . . . . . . . . . . . . . . . .
2.2 Stellar physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.1 Magnetic activity and variability . . . . . . . . . . . . . . . . . . .
2.2.1.1 Structure and modelling of the stellar chromospheres and
coronae . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.1.2 Magnetic structures in the photospheres, chromospheres
and coronae of single stars and close binary systems . . . .
2.2.1.3 Systematic observations and activity cycles . . . . . . . .
2.2.1.4 Orbital period modulation and magnetic activity cycle in
close binaries . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.1.5 Evolution of stellar magnetic activity and related phenomena
2.2.1.6 Dynamo theory of stellar magnetic activity . . . . . . . .
2.2.1.7 Space projects to study stellar activity and variability . .
2.2.2 Stellar oscillations and asteroseismology . . . . . . . . . . . . . . .
2.2.2.1 Asteroseismology of hot subdwarf stars . . . . . . . . . . .
2.2.2.2 Orbital period modulation and oscillation in magnetically
active close binaries . . . . . . . . . . . . . . . . . . . . .
2.2.3 Chemical composition studies and chemically peculiar stars . . . . .
2.2.3.1 Extremely metal-poor stars . . . . . . . . . . . . . . . . .
2.2.3.2 Chemically peculiar stars . . . . . . . . . . . . . . . . . .
2.2.3.3 Spectral variability in chemically peculiar stars . . . . . .
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CONTENTS
2.2.3.4 Measurement of magnetic fields in chemically peculiar stars
Formation and evolution of stars . . . . . . . . . . . . . . . . . . .
2.2.4.1 Hot stars in Local Group galaxies . . . . . . . . . . . . . .
2.2.4.2 Stellar Populations studies using HST . . . . . . . . . . .
2.2.4.3 Star formation in the bulge of M51 . . . . . . . . . . . . .
2.2.4.4 Searches for brown dwarfs . . . . . . . . . . . . . . . . . .
2.2.4.5 The radio emission of β Lyrae . . . . . . . . . . . . . . . .
2.2.4.6 Nuclear Astrophysics . . . . . . . . . . . . . . . . . . . . .
2.2.4.7 Accretion disk models . . . . . . . . . . . . . . . . . . . .
2.2.4.8 Determination of the physical parameters of close binaries
2.2.5 Search for extra-solar planets . . . . . . . . . . . . . . . . . . . . .
Extra-galactic Astrophysics and Cosmology . . . . . . . . . . . . . . . . . .
2.3.1 Cosmology: Galaxy Formation . . . . . . . . . . . . . . . . . . . . .
2.3.2 Cosmology: Universe models . . . . . . . . . . . . . . . . . . . . . .
2.3.3 Extra-galactic astrophysics: U B V photometry of BL Lac objects,
Gamma Ray burts observation . . . . . . . . . . . . . . . . . . . . .
Laboratory of experimental astrophysics and Solar System physics . . . . .
2.4.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.2 Experimental facilities . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.2.1 The Vacuum Chamber . . . . . . . . . . . . . . . . . . . .
2.4.2.2 The Ion Implanter . . . . . . . . . . . . . . . . . . . . . .
2.4.2.3 Upgrade of the ion implanter . . . . . . . . . . . . . . . .
2.4.2.4 The UV lamp . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.2.5 Infrared Spectroscopy . . . . . . . . . . . . . . . . . . . .
2.4.2.6 Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . .
2.4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.3.1 Comparison of ion irradiation and UV photolysis of ices .
2.4.3.2 Ion irradiation of frozen hydrocarbons . . . . . . . . . . .
2.4.3.3 C60 Fullerene . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.3.4 Nitrogen condensation on water ice . . . . . . . . . . . . .
2.4.3.5 Asteroids photometry . . . . . . . . . . . . . . . . . . . .
2.4.3.6 Future studies . . . . . . . . . . . . . . . . . . . . . . . .
Catania Observatory Laboratory for Detectors (COLD) . . . . . . . . . . .
2.5.1 CCD controller update . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.1.1 CCD controller for TNG . . . . . . . . . . . . . . . . . . .
2.5.2 New technology detectors . . . . . . . . . . . . . . . . . . . . . . .
2.5.2.1 CVD Diamonds detectors . . . . . . . . . . . . . . . . . .
2.5.2.2 Intensified Active Pixel Sensor (IAPS) . . . . . . . . . . .
2.5.2.3 SPAD detector . . . . . . . . . . . . . . . . . . . . . . . .
2.5.3 Collaboration with Industries . . . . . . . . . . . . . . . . . . . . .
2.5.4 Support for CCD Cameras and control systems . . . . . . . . . . .
2.5.4.1 The CCD camera for the Schmidt telescope at Serra La
Nave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.4.2 Support to solar and stellar observations . . . . . . . . . .
2.5.4.3 Support to the Schmidt Telescope at Cima Ekar . . . . . .
2.5.5 International project collaboration . . . . . . . . . . . . . . . . . .
Computational technologies for astrophysics . . . . . . . . . . . . . . . . .
2.2.4
2.3
2.4
2.5
2.6
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CONTENTS
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
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Introduction . . . . . . .
FLY: a parallel tree-code
Scientific Visualization .
Grid Computing . . . .
Conclusion . . . . . . . .
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3 Projects and Collaborations
3.1 Space projects . . . . . . . . . . . .
3.2 National and international projects
3.3 Staff involved in projects . . . . . .
3.4 Collaborations . . . . . . . . . . . .
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cosmological N-Body
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simulations
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4 Facilities and Services
4.1 Buildings . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Training and courses attended by the staff members . .
4.3 Acquisition of new instrumentation and facilities . . . .
4.4 Library . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5 Computing Center and local network . . . . . . . . . .
4.6 Opto-mechanical workshop and telescopes’ automation
4.6.1 Telescope automation . . . . . . . . . . . . . . .
4.6.2 Opto-mechanical laboratory . . . . . . . . . . .
4.7 CCD image acquisition . . . . . . . . . . . . . . . . . .
4.8 Photometric data acquisition and reduction . . . . . .
4.9 The ”Mario G. Fracastoro” station on Mt. Etna . . . .
4.10 Solar observation facilities . . . . . . . . . . . . . . . .
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5 Out-reach and Education
5.1 Out-reach Office . . . . . . . . . . . . . . . . . . . . . .
5.1.1 Public conferences . . . . . . . . . . . . . . . .
5.1.2 Visits to the Observatory . . . . . . . . . . . . .
5.1.3 Special events . . . . . . . . . . . . . . . . . . .
5.2 Advanced course on detector technology . . . . . . . .
5.3 University Courses and high level Educational Activity
5.4 Ph.D. Students . . . . . . . . . . . . . . . . . . . . . .
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6 Staff members
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6.1 Staff on 31 December 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
List of Publications 2002
7.1 Papers on refereed Journals . . . . . . . . . . . . . . .
7.1.1 In press . . . . . . . . . . . . . . . . . . . . . .
7.2 Invited talks . . . . . . . . . . . . . . . . . . . . . . . .
7.2.1 In press . . . . . . . . . . . . . . . . . . . . . .
7.3 Contributed papers to international meetings . . . . . .
7.3.1 In press . . . . . . . . . . . . . . . . . . . . . .
7.4 Electronic publications, short articles, technical reports
A Sommario del bilancio OACt 2002
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CONTENTS
List of Tables
1
Catania Astrophysical Observatory, e-mail/phone directory . . . . . . . . . xvi
2.1 Stellar physics: Parameters obtained from analytical solutions . . . . . . . 21
2.2 APT80/1 target stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.1 Projects and collaboration: Projetcs titles . . . . . . . . . . . . . . . . . . 82
3.2 Projetcs and collaboration: OACt researchers Projects . . . . . . . . . . . 84
4.1 MG Fracastoro station: Telescopes activity . . . . . . . . . . . . . . . . . . 102
A.1 Entrate (in kEU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
A.2 Spese (KEU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
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LIST OF TABLES
List of Figures
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14
2.15
2.16
2.17
2.18
2.19
2.20
2.21
2.22
2.23
2.24
2.25
2.26
Solar Physics: EIT images of CME (November 1-3 2000) . . . . . . . . .
Solar Physics: Average loop density . . . . . . . . . . . . . . . . . . . . .
Solar Physics: Adiabatic exponent Γ1 . . . . . . . . . . . . . . . . . . . .
Solar Physics: Vulcano Meeting poster . . . . . . . . . . . . . . . . . . .
Stellar physics: HR 1099 flaring, observed line profiles . . . . . . . . . . .
Stellar physics: HR 1099 V-band and spot model . . . . . . . . . . . . .
Stellar physics: VY Ari effective temperature as a function of rotational
phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stellar physics: VY Ari, solutions for the temperature and light curve
amplitudes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stellar physics: HK Lac, longitude shifts between spots and plages . . . .
Stellar physics: BY Dra, V-band photometry . . . . . . . . . . . . . . . .
Stellar physics: V711 Tau, V-band photometry . . . . . . . . . . . . . . .
Stellar physics: RT Lac, total spot area . . . . . . . . . . . . . . . . . . .
Stellar physics: DX Leo, time sequence of V-band magnitudes . . . . . .
Stellar physics: EK Dra, time sequence of V-band magnitudes . . . . . .
Stellar physics: V-band cycles on EK Dra, Q Hya, AB Dor and the Sun .
Stellar oscillations and asteroseismology: η Bootis evolutionary tracks . .
Stellar oscillations and asteroseismology: Observed and computed frequencies for η Boo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stellar oscillations and asteroseismology: The variation of the splitting
coefficients ∆a1 for three p-modes . . . . . . . . . . . . . . . . . . . . . .
Chemical composition studies: HD 207538, comparison between theoretical
and observed spectra in the FUV range 1000 - 1098 Å . . . . . . . . . . .
and observed spectra in the FUV range 1098 - 1188 Å . . . . . . . . . . .
and observed spectra in the IUE range . . . . . . . . . . . . . . . . . . .
and observed spectra in the visual range . . . . . . . . . . . . . . . . . .
Chemical composition studies: Helium lines observed in the visible spectrum of HD 207538 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chemical composition studies: Equivalent width variations of HD 124224
versus phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chemical composition studies: Equivalent width variations of HD 142990
Chemical composition studies: Behavior of equivalent width versus effective
temperature for our sample of CP stars . . . . . . . . . . . . . . . . . . .
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LIST OF FIGURES
2.27 Chemical composition studies: Simultaneous fit of the composite Hβ of
HD 191110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.28 Formation and evolution of stars: Normalized spectra of stars observed in
M 33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.29 Formation and evolution of stars: HR diagram for the 13,098 stars detected
in the control field for SN1987A . . . . . . . . . . . . . . . . . . . . . . .
2.30 Stellar physics: RT Lacertae, systemic RV . . . . . . . . . . . . . . . . .
2.31 Extra-solar planets: The radial velocity of HD 219542b . . . . . . . . . .
2.32 Extra-solar planets: The TSI variation with superposed the central transit
of an Earth-like planet . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.33 Cosmology: Galaxy structure simulation . . . . . . . . . . . . . . . . . .
2.34 Astrophisycs Laboratory: Apparatus . . . . . . . . . . . . . . . . . . . .
2.35 Astrophisycs Laboratory: Possible experiments . . . . . . . . . . . . . . .
2.36 Astrophisycs Laboratory: Upgraded implanter . . . . . . . . . . . . . . .
2.37 Astrophisycs Laboratory: Irradiated CH4 . . . . . . . . . . . . . . . . . .
2.38 Detectors lab: Large area diamond device Q.E. . . . . . . . . . . . . . .
2.39 Detectors lab: CMOS-APS photon counting system . . . . . . . . . . . .
2.40 Detectors lab: SPAD devices Q.E. . . . . . . . . . . . . . . . . . . . . . .
2.41 Detectors lab: Response of near UV multilayers filters for UVISS . . . .
2.42 Computational tech.: IBM SP 9076 . . . . . . . . . . . . . . . . . . . . .
2.43 Computational tech.: Main FLY window . . . . . . . . . . . . . . . . . .
2.44 Computational tech.: The main GUI of AstroMD . . . . . . . . . . . . .
2.45 Computational tech.: Formation of clusters of galaxies simulation . . . .
2.46 Computational tech.: LCDM model simulation at z=0 . . . . . . . . . .
2.47 Computational tech.: LCDM model Correlation Function . . . . . . . . .
2.48 Computational tech.: Minkowski Functionals of a LCDM simulation . . .
2.49 Computational tech.: The Astrocomp Portal . . . . . . . . . . . . . . . .
4.1
4.2
4.3
4.4
Library: Solar spot drawing (Secchi 1875)
Library: Solar eclipse (Tacchini 1888) . . .
Solar facilities: The equatorial spar . . . .
Solar facilities: Hα a image of the Sun . .
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Foreword
Premessa
Lo scopo di questo rapporto è di presentare i risultati dell’attività dell’Osservatorio Astrofisico di Catania nel corso dell’anno solare 2002 sul piano scientifico, tecnologico e di
promozione culturale e scientifica nella scuola e nella società. Esso offre inoltre un utile
strumento di documentazione rivolto alle istituzioni, locali e nazionali, che nell’anno 2002
hanno in vario modo sostenuto le attività dell’Osservatorio o hanno avuto rapporti con
esso, alle quali va il più vivo ringraziamento.
L’Osservatorio Astrofisico di Catania (OACt) fa parte della rete di dodici Osservatori dell’Istituto Nazionale di Astrofisica e dispone di due sedi. La principale è ubicata
all’interno della Cittadella Universitaria, e comprende gli uffici, i Laboratori di ricerca,
le officine ottico-meccaniche, e il telescopio per le osservazioni solari. La seconda sede,
intitolata a Mario Girolamo Fracastoro, é collocata in località Serra La Nave sul versante
sud-est dell’Etna a quota 1750 m s.l.m. Essa è la sede osservativa dotata di quattro
telescopi ed una foresteria.
L’Osservatorio opera in stretta collaborazione con la sezione Astrofisica del Dipartimento di Fisica e Astronomia dell’Università di Catania, che ha sede nel suo stesso edificio.
Ivi si svolgono le attività di insegnamento, i corsi per il Dottorato di Ricerca, le attività
connesse ai laboratori didattici, e le conferenze.
Foreword
The aim of this report is to present the main results achieved by Catania Astrophysical Observatory during 2002, in research, technological development, and dissemination
of the scientific culture in the schools and the society. It offers a detailed documentation
on all of the Observatory’s activities and facilities and it is addressed, among others,
to the Institutions that have supported the Observatory during 2002, which are deeply
acknowledged.
The Catania Astrophysical Observatory (OACt) is one of the twelve Observatories of
the network of the Istituto Nazionale di Astrofisica and it has two separate seats. The
main center is seat inside the Catania University Campus, where research offices, library,
laboratories, opto-mechanic workshops, and the solar observing station are located. The
second one, dedicated to Mario Girolamo Fracastoro, is a mountain observing station on
the south-west side of Mt. Etna at 1750 m a.s.l., where four telescopes and a guesthouse
are located.
The Catania Astrophysical Observatory strictly co-operates with the Astrophysical
xi
xii
FOREWORD
Section of the Physics and Astronomy Department of the Catania University, hosted in
the same building of the Observatory. There university and Ph.D. courses are usually held
together with the training laboratory activities for the students and public conferences.
Prof. Santo Catalano
(Director)
Osservatorio Astrofisico di Catania:
Staff directory 2002
Director
Catalano Santo
Board
Belvedere G., Cutispoto G., Del Popolo S., Frasca A., Miraglia M., Pagano I., Strazzulla
G., Rapisarda M.L., Scuderi S.
Name
Catania Astrophysical Observatory, e-mail/phone directory
Position
e-mail
@ct.astro.it
ANTONUCCIO Vincenzo
BARATTA Giuseppe
BECCIANI Ugo
BELLASSAI Giancarlo
BELLUSO Massimiliano
BONANNO Alfio
BONANNO Giovanni
BRUNO Pietro
BUSÀ Enza
CALÌ Antonio
CALÌ Maddalena
CARBONARO Giuseppe
CARIPOLI Giuseppe
CARUSO Maria Rita
CASTORINA Giovanni
Research Astronomer
Associate Astronomer
Research Astronomer
Technical Staff
Technical Staff
Research Astronomer
Full Astronomer
Technical Staff
Research Astronomer
Technical Staff
Technical Staff
Technical Staff
Library
MGF* site Staff
Technical Staff
van
gbaratta
ube
gbellassai
mbelluso
abo
gbonanno
pbruno
ebu
acali
gcarbonaro
gcaripoli
phon ext
+39095-7332
318
313, 265
317
303
279
319
204, 254
205
261
205
248
201, 203
210
095 911580
208, 209
continued on next page
xiii
xiv
OSSERVATORIO ASTROFISICO DI CATANIA: STAFF DIRECTORY 2002
continued from previous page
Name
Position
CATALANO Santo
CATANZARO Giovanni
CATINOTO Enrico
CORSARO Gaetano
COSENTINO Rosario
COSTA Alessandro
COSTA Pierfrancesco
CUTISPOTO Giuseppe
DEL POPOLO Santa
Full Astronomer
Research Astronomer
Technical Staff
MGF* site Staff
Research Astronomer
Computer Center
Administrative Staff
DI BENEDETTO Rosario
DI MAURO Maria Pia
DISTEFANO Antonio
DOMINA Daniela
FRASCA Antonio
GENTILE Giovanni
GIUFFRIDA Alfio
GRECO Vincenzo
LAMPÒ Rocco
LANZA Antonino F.
LANZAFAME Giuseppe
LEONE Franco
LETO Giuseppe
LO PRESTI Carmelo
MAGAZZÙ Antonio
MANGANO Angela
Technical Staff
Research Astronomer
Technical Staff
Library
Research Astronomer
Technical Staff
Computer Center
Technical Staff
Technical Staff
Research Astronomer
Research Astronomer
Research Astronomer
Research Astronomer
Research Astronomer
Library
MARILLI Ettore
MARTINETTI Eugenio
MASSIMINO Piero
MELLINI Maria
MESSINA Sergio
MICCICHÈ Antonio
MIRAGLIA Massimo
OCCHIPINTI Giovanni
PAGANO Isabella
PALUMBO M.Elisabetta
PULEO Giuseppe
RAPISARDA Maria Luisa
Technical Staff
Computer Center
Research Astronomer
MGF* site Staff
Technical Staff
MGF* site Staff
Research Astronomer
Research Astronomer
Technical Staff
RECUPERO Daniela
ROMANIA Valentina
Library
e-mail
@ct.astro.it
scat
gca
ecatinoto
scor
rco
alex.costa
pcosta
gcutispoto
sdelpopolo
segreteria
sdibenedetto
mdm
adistefano
ddomina
afrasca
ggentile
agiuffrida
vgreco
rlampo
nlanza
glanzafame
fleone
gle
clopresti
antonio
amangano
library
emarilli
emartin
pmassimino
amministr
sme
mmiraglia
ipagano
mepalumbo
mpuleo
mlrapisarda
amministr
drecupero
vromania
phon ext
+39095-7332
219,222
332
232, 253
095 911580
260, 259
273
264
312
226
226
205
207
200
268
240
201, 203
257, 218
200
300
238
316
229
311, 265
215
248
248
246
304
216
225
230, 305
095 911580
256, 203
095 911580
243
242, 265
201, 203
224
224
247
262
xv
Name
Position
SACCONE Rosaria
SANTAGATI Luigia
SANTOCONO Orazio
SARDONE Stefano
SCAFILI Marcella
SCIUTO Santo
SCUDERI Cosimo
SCUDERI Salvo
SPADARO Daniele
SPINELLA Franco
STRAZZULLA Giovanni
TERNULLO Maurizio
TIMPANARO M.Cristina
TRINGALE Gaetana
VENTIMIGLIA Agata
VENTURA Rita
WANAUSEK Antonino
ZINGALE Giuseppe
Library
Technical Staff
Technical Staff
MGF* site Staff
Research Astronomer
Research Astronomer
Technical Staff
Full Astronomer
Research Astronomer
Technical Staff
Technical Staff
Research Astronomer
Technical Staff
Technical Staff
e-mail
@ct.astro.it
gsantagati
ssardone
mscafili
ssciuto
sscuderi
dspadaro
fspinella
gianni
mternullo
mctimpanaro
segreteria
rventura
awanausek
phon ext
+39095-7332
227
269
208, 209
306
263
232, 233
095 911580
255
234
314, 265
315, 265
231
205
228, 226
208, 209
258
302
209, 208
Department of Physics and Astronomy-University of Catania
Astrophysics section
Director
BELVEDERE Gaetano
BELVEDERE Gaetano
ANASTASI Clelia
BLANCO Carlo
CATALANO Franco
LANZAFAME Alessandro
MARINO Eliana
PATERNÒ Lucio
RODONÒ Marcello
SPAMPINATO Cinzia
ZAPPALÀ Aldo
ZUCCARELLO Francesca
Associate Professor
Associate Professor
Associate Professor
Researcher
Full Professor
Full Professor
Associate Professor
Associate Professor
gbelvedere
canastasi
cblanco
fcatalano
acl
lpaterno
mrodono
razappala
fzucca
236
211
245
221
239
210
235
220
214
241
237
Ph.D. Students and Fellows
BIAZZO Katia
BENTIVEGNA Eloisa
CONTARINO Lidia
Fellowship
Fellowship
Ph. D. Student
kbi
lcont
330
xvi
OSSERVATORIO ASTROFISICO DI CATANIA: STAFF DIRECTORY 2002
Name
Position
COSTA Vincenzo
DI GIORGIO Salvatore
DI STEFANO Carla
Di STEFANO Elisa
FERINI Graziella
FERRO Daniela
LECCIA Silvio
MURABITO Annalisa
PALAZZO Giusimelissa
PIZZONE Gianluca
ROMANO Paolo
ROMEO Alessio
VENTURA Marianna
Post Doc Fellowship
Ph. D. Student
Ph. D. Student
Fellowship
Fellowship
Fellowship
Ph. D. Student
Ph. D. Student
Ph. D. Student
Ph. D. Student
Ph. D. Student
Ph. D. Student
Ph. D. Student
e-mail
@ct.astro.it
vcosta
cdi
dfe
amu
gpal
prom
mve
Table 1: Catania Astrophysical Observatory, e-mail/phone directory
* MGF: Mario Girolamo Fracastoro
phon ext
+39095-7332
325
328
327
329
Chapter 1
Report OACt 2002
Summary/Highlight
Introduzione al rapporto dell’OACt per l’anno 2002
Il 2002 ha segnato una svolta nella struttura organizzativa e amministrativa dell’ Osservatorio Astrofisico di Catania, che con gli altri Osservatori italiani è entrato a far parte
dell’ Istituto Nazionale di Astrofisica come struttura a tempo indeterminato. A decorre
dall’ 1 Gennaio 2002 lo scrivente è stato nominato direttore dell’ OAC per il triennio 20022004. In questo nuovo quadro normativo è stato costituito il Consiglio di Osservatorio
chiamando a farne parte, in aggiunta ai membri di diritto, il responsabile della Sezione
di Astrofisica del Dipartimento di Fisica ed Astronomia dell’ Università di Catania a
continuazione della stretta collaborazione tra l’ Osservatorio e l’ Università di Catania.
Le attività dell’anno 2002 sono state fortemente condizionate dai lavori di ristrutturazione e recupero dell’ edificio principale della sede di Catania, effettuati a cura dell’
Università di Catania. Le operazioni di spostamento e la sistemazione temporanea in
locali insufficienti, legati a tali lavori di ristrutturazione, hanno costretto i ricercatori
ed il personale tutto a lavorare in condizioni di estremo disagio, per tutta la seconda
parte dell’anno. Tuttavia le attività scientifiche sono proseguite con elevato standard ed
il personale tutto ha svolto i propri compiti con serietà e piena coscienza del senso dell’
istituzione.
L’ Osservatorio di Catania con le stazioni eliofisica e dell’ Etna (Serra La Nave) rimane
uno dei pochi osservatori in Italia in cui l’attività osservativa locale prosegue ad alti
livelli di continuità e di qualità con inserimento in programmi nazionali ed internazionali.
All’attività osservativa si affianca una intensa attività di ricerca nel campo della fisica
stellare e solare di riconosciuta valenza nazionale ed internazionale. Presso l’Osservatorio
operano inoltre il laboratorio di astrofisica sperimentale, il laboratorio dei rivelatori per
l’ astrofisica e il laboratorio di calcolo ad alte prestazioni. L’ attività di ricerca svolta nel
2002 si puó suddividere a grandi linee in:
Fisica solare. Le ricerche di fisica solare si sviluppano su linee di tipo osservativo,
che utilizzano facilities internazionali da terra e dallo spazio, e di tipo teorico. Esse comprendono studi di fisica della corona solare, modelli idrodinamici e di riscaldamento del
complesso cromosfera-TR-corona, modelli dinamo con circolazione meridiana, eliosismologia e struttura interna. Un aspetto rilevante delle osservazioni sistematiche del Sole è dato
dall’inserimento nel Global Hα Network organizzato dal Big Bear Solar Observatory e
1
2
CHAPTER 1. REPORT OACT 2002 SUMMARY/HIGHLIGHT
nel programma di ricerca sullo Space Weather attraverso campagne di Flare Warning.
Fisica stellare. Gli studi di fisica stellare presso l’ Osservatorio Astrofisico di Catania
costituiscono il programma di ricerca più corposo ed articolato, con una parte prevalente
dedicata all’ attività magnetica stellare in stelle singole e doppie, dalla fotosfera alla
corona con osservazioni e modelli; oscillazioni stellari e problematiche di struttura stellare
con attività teorica ed osservativa; composizione chimica e stelle chimicamente peculiari;
problemi osservativi di formazione ed evoluzione stellare; processi nucleari di interesse
astrofisico.
Ammassi di galassie, cosmologia. Si tratta di un gruppo di piccole dimensioni
che si occupa di modellizzazione del plasma intergalattico e dei processi di riscaldamento
di Ammassi di Galassie mediante codici paralleli a N-corpi e codici euleriani a griglia
adattiva, modelli di generazione e propagazione di raggi cosmici di energie estreme in
strutture a Grande Scala dell’ Universo.
Laboratorio di Astrofisica Sperimentale. Le ricerche si riferiscono alle interazioni
tra radiazione e materia in ambienti di interesse astrofisico, con sperimentazione delle
modificazioni chimico-fisiche di bersagli solidi (silicati, materiali carboniosi, gas congelati)
bombardati con fasci ionici energetici (3-200 keV) o con fotoni ultravioletti (Lymanalpha 121.6 nm, ovvero 10.2 eV). Nel 2002 è stato effettuato l’ upgrading a 200 keV dell’
impiantatore di ioni, che aprirà nuove ed importanti prospettive sperimentali a valori di
energie ancora inesplorati.
Laboratorio rivelatori per l’ Astronomia. L’ attività dal gruppo di ricerca sui rivelatori si articola in due aspetti principali: sviluppo di elettronica e software di controllo di
rivelatori CCD, sviluppo e caratterizzazione di rivelatori di nuova generazione. In questo
ultimo contesto sono da evidenziare lo sviluppo di rivelatore a conteggio di fotoni basato
su ”Intensified CMOS-APS” (IAPS), sviluppo di un sensore a matrice di ”Single
photon avalanche diodes’ (SPAD) in collaborazione con ST Microelectronics, di
Catania, caratterizzazione di un rivelatore a diamante sintetico in collaborazione con il
Dipartimento di Astronomia e Scienza dello Spazio dell’Università di Firenze ed altri istituti italiani. Il gruppo è fortemente impegnato nell’upgrade dei sistemi di acquisizione
di immagini del TNG, e dei telescopi dell’ OAC.
Calcolo ad alte prestazioni e visualizzazione scientifica (HPC). Il sistema di
calcolo parallelo, realizzato tramite il progetto ”Alta formazione nel campo del calcolo ad
alte prestazioni e problematiche astrofisiche attuali” del MURST su finanziamenti dell’
Unione Europea, ha ricevuto nel 2002 un ulteriore finanziamento per l’ upgrading delle
macchina di calcolo. Oltre allo sviluppo di codici paralleli nel campo della simulazione dell’
evoluzione delle galassie il programma prevede lo sviluppo di pacchetti di visualizzazione
ed analisi specificamente orientati a dati di simulazioni e di archivio (AstroMD), calcolo e simulazioni su griglia computazionale (GRID) con gestione remota di simulazioni
(AstroComp), orientati verso il Virtual Observatory
L’ attività dell’ Osservatorio nel campo dell’ alta formazione anche nel 2002 ha
trovato un notevole impegno, anche finanziario con il pagamento di una borsa di studio
per il XIII Ciclo di Dottorato di Ricerca in convenzione con l’ Università di Catania e
la partecipazione come Socio Ordinario al Consorzio dell’ Istituto Superiore di Catania
per la Formazione di Eccellenza, con la collaborazione con il Dipartimento di Fisica ed
Astronomia nella didattica universitaria (parte di corsi, supporto ai corsi di laboratorio,
esperienze di osservazioni astronomiche) e di dottorato. Astronomi dell’ Osservatorio sono
relatori di tesi di Laurea e tutor di tesi di Dottorato. Anche nel 2002 è stato effettuato
3
presso la sede M. G. Fracastoro uno stage di una settimana per gli studenti di fisica ed
ingegneria della Scuola di Eccellenza di Catania.
Questo documento descrive le attività di ricerca e lo sviluppo dell’ Osservatorio Astrofisico di Catania svolte nel 2002. Considerata la stretta collaborazione con la Sezione
Astrofisica del Dipartimento di Fisica ed Astronomia in questo documento vengono descritte anche le attività di tale gruppo in una presentazione unitaria come risultato delle
sinergie proficue della integrazione delle due istituzioni nella stessa struttura.
OACt 2002 report summary/highlight
The year 2002 has been characterized by profound changes in the administrative and
organization structure of the Catania Astrophysical Observatory, which from January 1st
2003, together with the other italian Observatories joined the National Institute for Astrophysics (INAF). Starting from the same date the writer was appointed as Director for
the triennium 2002-2004. In the framework of this new assessment the Observatory Board
(Consiglio di Osservatorio) was settled with the Chairman of the Astrophysics Section of
the Department of Physics and Astronomy of the Catania University appointed as additional member, in order to maintain the close collaboration and synergy between the two
institutions.
All activities in 2002 have been strongly hampered by renewal construction of the main
building of the Città Universitaria center. The work has been funded and handled by the
Catania University. The empting operation of the building and temporary settling on
inadequate crowded offices have compelled researchers and all personnel to work in a very
comfortless condition, during the second part of the year. However, research activities
have been continued at high scientific level and all the personnel has performed at high
efficiency level and awareness of duty.
The Catania Observatory with the eliophysics station and the mountain station on
Etna (Serra La Nave) remains one of the few italian astronomical institutions where observational activities are pursued with continuity and high quality level, within national and
international collaborations. The observational activities are complemented by theoretical and data analysis researches in the fields on solar and stellar physics well recognized
in the national and international context. The Catania Observatory includes also well
equipped laboratories e.g. the Laboratory for Experimental Astrophysics, the Laboratory
of Detectors for Astronomy and the High Performance Computing Laboratory. Research
activities pursued in 2002 can be grouped within the following main fields:
Solar Physics. Research on solar physics includes observations based activities,
which use international ground-based and space facilities, and theoretical researches. All
these researches relate to physical studies of the solar corona, hydrodynamic models,
heating mechanisms of the chromosphere-Transition Region complex, dynamo models
which include meridian circulation, elioseismology and internal structure of the Sun. A
relevant aspect of the systematic solar monitoring is the participation into the Global
Hα Network coordinated by the Big Bear Solar Observatory and into the Space Weather
program through Flare Warning campaigns.
Stellar Physics. Studies on stellar physics constitute the main body of research
at Catania Astrophysical Observatory . The more relevant part relates to the magnetic
4
activity studies on single and binary stars, from the photosphere to the corona from
observational and theoretical point of view. Stellar oscillations and internal structure of
stars, chemical composition, chemically peculiar stars, as well as observational aspects of
formation and evolution of stars with related problems of nuclear processes of astrophysical
interest are also investigated.
Clusters of galaxies and cosmology. This relatively small group recently formed is
working in modelling the intergalactic plasma and on the heating processes of clusters of
galaxies by means of N-body parallel, numerical codes and eulerian codes with adaptive
grids, as well as on models for the generation and propagation of extremely energetic
cosmic rays in large structures of the universe.
Laboratory for Experimental Astrophysics. Researches in this lab refer to the
experiments on the interaction of radiation with iced material in environment of astrophysical interest. Chemical and physical modifications induced on solid targets (silicate,
carbon materials, and iced gas) by bombardment with energetic ion beams (3-200 keV)
or UV photons (Lyman-α 121,6 nm = 10,2 eV). During the year 2002 the ion implanter
was upgraded to 200 keV, thus opening a new window of experiments at energy levels not
yet well explored.
Laboratory of detectors for Astronomy. The activity of the research group is
devoted to two main activities: development of control electronics and software for CCD
detectors, implementation and characterization of new technology detectors. Within the
latter activity it is worth to mention the preparation of photon counting imaging system based on Intensified CMOS-APS (IAPS) , implementation of ”Single Photon
Avalange Diodes” (SPAD) matrix in collaboration with the Catania R&D section of
the ST Microelectronics, and characterization of a detector based on synthetic diamond
in collaboration with the Department of Astronomy and Science of Space of Florence University. Furthermore the group is deeply engaged in the improvement and upgrading of
the image acquisition systems of the Galileo National Telescope (TNG) and of the Catania
telescopes.
High Performance Computation (HPC) and scientific visualization. The
parallel computing system, implemented within the special project ” Alta formazione nel
campo del calcolo ad alte prestazioni e problematiche astrofisiche attuali” of the MURST
on the base of EU funds, has received further support in 2002 for the upgrading of computing machines. In addition to parallel numerical codes in the field of galaxies simulation
models, the program is devoted to the development of visualization packages specially oriented to archive and simulation data (AstroMD), computation and simulation on computational grid (GRID) with remote management (AstroComp) orinted to the Virtual
Observatory
Also in 2002 the Observatory has payed special attention to the field of high formation
with financial support within a special agreement with the Catania University for a PhD
in Physics fellowship for the XVIII cycle and the partnerhips in the Consorzio dell’ Istituto
Superiore di Catania per la Formazione di Eccellenza. Collaboration with the Department
of Physics and Astronomy of the Catania University for the academic activities, i.e delivery
of university and PhD courses, use of observatory labs and telescopes for the experimental
and practical exercises. Astronomers of the observatory are currently tutors for the Degree
or PhD thesis work. One week stage at the M.G. Fracastoro mountain station was given
for Physics and Engineer students of the Catania Excellence School.
The present document is aimed to the description of research activity and development
5
of Catania Astrophysical Observatory achieved in 2002. Taking into account the tight
collaboration with the Astrophysics Section of the Department of Physics and Astronomy
of the Catania University, the activities of both institutions are presented in this document
to stress the positive effects of the unitary scientific policy.
Prof. Santo Catalano
(Director)
6
Chapter 2
Research
2.1
Solar Physics
INAF Researchers:
Catania University Researchers:
PhD Students:
A. Bonanno, M. P. Di Mauro, A. F. Lanza,
D. Spadaro, M. Ternullo, R. Ventura
G. Belvedere, A. C. Lanzafame, L. Paternò,
F. Zuccarello
L. Contarino, A. Murabito, P. Romano., S. Di Giorgio
Solar physics studies carried out in Catania cover nearly all the regions of the Sun,
from its interior, to the surface and corona, and out to the solar wind. In addition to the
traditional activities concerning the systematic patrol of solar activity, the structure and
the dynamics of the solar interior, the theoretical investigation about the generation and
evolution of magnetic fields, the study of the rotational characteristics have been carried
out. Recently, there has been a significant involvement in space missions devoted to the
observations of the solar atmosphere, in particular the ESA/NASA Solar and Heliospheric
Observatory (SOHO) and the NASA Transition Region and Coronal Explorer (TRACE).
This allowed the development of activities concerning the spectroscopic diagnostics and
modelling of coronal magnetic structures and of the solar wind source regions. Some solar
scientists from Catania are now actively involved in a scientific project selected for the
Solar Dynamics Observatory, a cornerstone mission within the NASA ’Living With a Star
(LWS)’ programme, whose purpose is to understand in more detail the nature and the
origin of the solar phenomena and variations that affect life and society.
More specifically, research activities have been conducted according to the following
scheme.
2.1.1
Systematic patrol of photospheric and chromospheric activity
The systematic observations of the Sun in white light and Hα line have been carried
on in the framework of an international collaboration aimed at performing the patrol of
solar activity. The data acquired within this project refer to: sunspots, faculae, quiescent
and active prominences on the disk and on limb, flares. These data are daily sent to
the various international collecting centers and put on the web page of the Observatory
7
8
CHAPTER 2. RESEARCH
[126, 141].
A ”Flare Warning” campaign recently started, within the international research programme on Space Weather. The campaign is based on the following operations:
• observations of active regions appearing on the solar disc, both in the photosphere
and chromosphere;
• comparison of the active regions configuration with that observed on the previous
day;
• comparison with the magnetograms available on Big Bear Observatory web page;
• singling out active regions which, according to some standard parameters, have the
highest probability to give rise to flares and/or filament eruptions;
• ”warning” e-mail to the national and international scientific community, as well as to
the teams of space experiments involved in the Space Weather research programme.
The final aim is to recognize in advance and to observe by both ground-based and space
telescopes solar events which are capable of producing troubles in satellite payloads, or
even in Earth-based instruments [65, 88, 89, 124, 126, 141]. Moreover, Catania Observatory collaborates to the Global High Resolution Hα Network and supports the activities
of the French-Italian solar telescope Themis (see sect. 4.10).
2.1.2
Solar wind and coronal mass ejections
D. Spadaro has collaborated to the study of the solar wind interaction with the interstellar
medium at the boundary of the heliosphere with observations made with UVCS/SOHO,
which were used to study the interplanetary He focusing cone within 1 AU. Taken over 2
yr and from differing orbit positions, the series of observations include measurements of He
I 584 Å and Lyβ intensities. This is the first time that interstellar helium is observed so
near the Sun. Measured intensities were compared to a detailed temperature and density
model of interstellar helium in the solar system. The model includes EUV ionization
but does not include ionization by electron impact from solar wind electrons. Important
day-to-day variations of the intensity were observed, as well as a general decrease as the
solar activity rose (both absolute and divided by a model with a constant ionization).
This shows that the helium intensity pattern is a very sensitive indicator of the electron
density and temperature near the Sun [21].
R. Ventura and D. Spadaro have carried out the analysis of the data acquired with the
Ultraviolet Coronagraph Spectrometer (UVCS) onboard the SOHO satellite and relevant
to the two coronal mass ejections (CME) observed on 2 and 3 November 2000, during
the simultaneous observational campaign with various SOHO instruments (MEDOC campaign # 6) held at the Institut d’Astrophysique Spatiale of Orsay-Paris. The two CMEs
were related to the eruptions of a large filament structure in an active region close to the
West limb of the Sun, and of a prominence near the South Pole, respectively. Intensity
and profile of the O VI resonance doublet lines at 1032 and 1037 Å and of Lyβ (1026 Å)
line, together with the intensity of some other less abundant ions, were observed using
the O VI channel of UVCS.
2.1. SOLAR PHYSICS
9
Figure 2.1: Sequence of EIT He II 304 Å images of the Sun taken the day before (November 1, 2000 -left panel) the occurrence of the CME, the day of the event (November 2,
2000 - middle panel) and the day after (November 3, 2000 - right panel). The UVCS
slit position on November 2 EIT observation (19:19 UT) is also reported together with
the OVI and Lyβ long-slit profiles. The vertical and horizontal axes are the spatial coordinates along the slit and the wavelengths, respectively. Shorter wavelengths are at
right and smaller polar angles at the bottom of each panel. The vertical extent is 40
arcmin; the covered wavelength range is 16 Å. The slit center, defined as the slit region
of minimum heliocentric distance is located at a P.A. equal to 270◦ . Three bright spots
identified and numbered progressively on the basis of their distance from it (in arcmin).
The grey scale of the He II 304 Å has been saturated in order to better distinguish the
structures involved in the eruption.
The analysis of these spectroscopic observations has allowed to get information about
the distributions of ionic densities and flow velocities in the solar coronal plasma ejected
during these transient events. Emission due to ions like C II to O VI indicates a temperature range between 104.5 and 105.5 K. The simultaneous observations of the two phenomena with EIT/SOHO and LASCO/SOHO helped to clarify the morphology of the bright
emission regions. The distribution of the plasma ejected in the interplanetary medium
is extremely complex: several strands of plasma irregularly distributed inside the CME
structures, whose temporal evolution is significantly different from each other, developed
during both events. The velocities determined for each bright element also give a complex
picture of the plasma kinematics characterizing these coronal mass ejections. The results
obtained provide some guidelines for the development of magnetohydrodynamic models
which describe the CME [27].
10
2.1.3
CHAPTER 2. RESEARCH
Spectroscopic diagnostic and modelling of coronal structures
D. Spadaro has discussed the importance of observations and analysis of EUV emission
lines for determining the physical structure and dynamics of the solar transition region
and corona [84]:
D. Spadaro, A.F Lanza and A.C. Lanzafame, in cooperation with colleagues of the
Naval Research Laboratory of Washington, DC and of the NASA Goddard Space Flight
Center of Greenbelt, MD, have investigated the hydrodynamic behavior of coronal loops
undergoing transient heating. This study was stimulated by a wealth of observational
evidence for flows and intensity variations in non-flaring coronal loops, that leads to the
conclusion that coronal heating is intrinsically unsteady and concentrated near the chromosphere. They carried out 1-D numerical simulations, in which the timescale assumed
for the heating variations (3000 s) is comparable to the coronal radiative cooling time and
the assumed heating location and scale height (10 Mm) are consistent with the values
derived from TRACE studies. The model loops represents typical active-region loops: 40
to 80 Mm in length, reaching peak temperatures up to 6 MK. Spadaro and co-workers
used ARGOS, a state-of-the-art numerical code with adaptive mesh refinement, in order
to resolve adequately the dynamic chromospheric-coronal transition region sections of the
loop. The new major results from this work are the following. (1) During much of the
cooling phase, the loops exhibit densities significantly larger than those predicted by the
well-known loop scaling laws (cf. Fig. 2.2), thus potentially explaining recent TRACE
observations of overdense loops. (2) Throughout the transient heating interval, downflows appear in the lower transition region (T ∼ 0.1 MK) whose key signature would
be persistent, redshifted UV and EUV line emission, as have long been observed. (3)
Strongly unequal heating in the two legs of the loop drives siphon flows from the more
strongly heated footpoint to the other end, thus explaining the substantial bulk flows in
loops recently observed by CDS and SUMER. The results of these studies have implications for the understanding of the physical origins of coronal heating and related dynamic
phenomena [49, 85, 86, 111, 122, 123].
A. Lanzafame, in collaboration with colleagues of the University of Strathclyde (Glasgow, UK), Rutherford Appleton Laboratory (UK) and Goddard Space Flight Center
(Greenbelt, Maryland) has investigated spectroscopic diagnostics for the solar transition
region and corona. The differential emission measure (DEM) of a solar active region is
derived from SERTS-89 rocket data between 170 and 450 Å. The integral inversion to infer the DEM distribution from spectral line intensities is performed by the data adaptive
smoothing approach. Their analysis takes into account the density dependence of both
ionisation fractions and excitation coefficients according to the collisional-radiative theory
as implemented in ADAS, the Atomic Data and Analysis Structure. Their strategy aims
at checking, using observational data, the validity and limitations of the DEM method
used for analysing solar EUV spectra. They investigate what information it is possible
to extract, within defined limitations, and how the method can assist in a number of
cases, e.g. abundance determination, spectral line identification, intensity predictions,
and validation of atomic cross-sections. Using the above data and theory, it is shown
that a spurious multiple peak in the DEM distribution between log(Te ) = 6.1 and 6.7,
where Te is the electron temperature, may derive from an inaccurate treatment of the
population densities of the excited levels and ionisation fractions or from using an inte-
2.1. SOLAR PHYSICS
11
11.5
11.0
Log <ne> (cm-3)
10.5
10.0
9.5
9.0
8.5
8.0
5.0
5.5
6.0
6.5
Log <T> (K)
Figure 2.2: Average loop density as a function of the average temperature during the
evolution of one of the loops obtained from the numerical simulations by Spadaro et al.
(dotted line, running counterclockwise) and from the scaling law theory (solid line, see
Rosner et al. 1978), gauged according to the initial static equilibrium. Different times are
indicated by the following symbols: initial condition (t = 0) – cross; near the maximum
heating rate (t = 1505 s) – asterisk; near the end of the transient heating (t = 3004 s) – x;
beginning of the downflow (t = 4800 s) – open diamond; significant downflow (t = 8520 s)
– open triangle; immediately before the catastrophic cooling (t = 9534 s) – open square;
restored initial condition (t = 28021 s) – open circle.
gral inversion technique with arbitrary smoothing. Therefore, complex DEM structures,
like those proposed for solar and stellar coronae by several authors, must be considered
with caution. We address also the issue of systematic differences between iso-electronic
sequences and show that these cannot be unambiguously detected in the coronal lines
observed by SERTS. Our results indicate that a substantial improvement is required in
the atomic modelling of the complex element Fe. The elemental abundance ratio Si/Ne
is found to be close to its photospheric value. The same result may be true for the Fe/Ne
abundance, but this latter result is uncertain because of the problems found with Fe [19].
2.1.4
Highly energetic transient events in the solar atmosphere
TRACE, owing to the wide range of wavelengths examined and to the high angular and
temporal resolution, gives the opportunity to carry out a spatial and temporal analysis of
active regions during highly transient phenomena such as flares, providing a new input to
the understanding of the mechanisms involved in these events. Zuccarello, Contarino and
Romano have studied 3 flares that occurred in AR 8421 between 29 and 30 December 1998
by comparing white light, 1600 Å , and 171 Å images obtained by TRACE, with BBSO
Hα images, Mitaka magnetograms and Yohkoh hard X-ray data. The flares, characterized
by sudden intensity enhancements in EUV loops and by moss brightenings, have been
interpreted in the framework of the two canonical flare models: i.e. simple loop and two
ribbon flares. The analysis has shown that the first flare may be interpreted as a tworibbon flare triggered by reconnection between a sheared arcade and a newly emerging
12
CHAPTER 2. RESEARCH
flux tube. The analysis of the second flare strongly supports the model of two-ribbon
flares characterized by reconnection occurring at higher and higher levels as time proceeds.
Finally, the analysis of the third flare has given the opportunity to relate moss brightening
with a probable process of chromospheric evaporation [51].
In the framework of the study on filament eruption, Romano, Contarino and Zuccarello
have analyzed the eruption of a prominence, characterized by a helical-like structure and
by a non-linear rising motion. The prominence was approximated as a cylindrically curved
flux tube and the behaviour of several geometrical parameters was estimated during the
activation and the eruption phases. It was determined that, at the onset of the activation,
the number N of turns of a magnetic field line over the whole length of the prominence
was ∼ 5.0, while the value of the ratio P/r0 between the pitch of the magnetic field lines
and the prominence width was ∼ 0.45. These values are in good agreement with those
predicted by the kink mode instability. Moreover, it was found a decrease of the total
twist of one helical thread from Φ ∼ 10π to Φ ∼ 2π during the prominence eruption,
indicating a relaxation of the magnetic field towards a less twisted configuration. It was
concluded that the prominence was initially destabilized by the kink mode instability and,
not succeeding in finding a new equilibrium configuration, it erupted [48, 82, 83, 121].
Moreover, Contarino, Romano and Zuccarello described a filament destabilization
which occurred on May 5, 2001 in NOAA AR 9445, before a flare event. The analysis is based on Hα data acquired by THEMIS operating in IPM mode, Hα data and
magnetograms obtained at the Big Bear Solar Observatory, MDI magnetograms and 171
Å images taken by TRACE. Observations at 171 Å show that ∼ 2.5 hours before the flare
peak, the western part of the EUV filament channel seems to split into two parts. The
bifurcation of the filament in the Hα line is observed to take place ∼ 1.5 hours before
the flare peak, while one thread of the filament erupts ∼ 10 minutes before the peak of
the flare. The analysis of longitudinal magnetograms shows the presence of a knot of
positive flux inside a region of negative polarity, which coincides with the site of filament
bifurcation. The event has been interpreted as occurring in two-steps: the first step, characterized by the appearance of a new magnetic feature and the successive reconnection in
the lower atmosphere between its field lines and the field lines of the old arcade sustaining
the filament, leads to a new filament channel and to the observed filament bifurcation;
the second step, characterized by the eruption of part of the filament lying on the old
PIL, leads to a second reconnection, occurring higher in the corona [66, 98].
Very energetic flares and CME may strongly influence Space Weather and Earth environment. In the last years, there has been growing interest in the possibility of forecasting
flare occurrence, in order to reduce damages to spacecrafts, satellite positioning systems
and effects on RF communications. In this context, Ternullo, Contarino, Romano and
Zuccarello have carried out a statistical analysis on a number of parameters characterizing sunspot-groups, hosting very energetic flares. The data used in the analysis concern
sunspot-groups, were partially collected at Catania Observatory during 1998 - 2002, partially deduced by NOAA reports, and partially on M and X flares obtained by GOES 8 in
the soft X-ray range. The results indicate that, for a given group, the probability of flaring
is related with its complexity, expressed by its large number of spots and pores, its large
area, its membership of some of the most evoluted Zürich types and with the asymmetry
of the penumbra of its largest spot. These results are fully compatible with the well-known
tendency of the magnetic flux toward reconnection in the presence of a complex magnetic
topology. Moreover, a large spot group offers a large “cross section” to newly buoyant
2.1. SOLAR PHYSICS
13
flux, so that destabilization and flaring are more easily triggered [65, 88, 89, 124, 126].
2.1.5
Emergence and evolution of solar active regions
The phase of formation of an active region consists in the buoyancy, at photospheric
level, of magnetic flux tubes which cause the formation of one or more pores. Next,
these pores may increase their area and number until they coalesce and form one or more
sunspots with penumbra and give rise to an AR. However, this process does not always
proceed with continuous evolution, because sometimes pores may disappear after 1-2 days.
Despite several studies carried out on this topic, it is not yet possible to forecast whether
the emergence of a group of pores might give rise to an active region, nor to obtain
information on the kind of evolution that the resulting AR may have. This question
was the main topic of two PICS (Programme International de Cooperation Scientifique)
Workshops, the former held in Catania in September 2001, the latter in Rome in October
2002. During these workshops Contarino, Romano, Spadaro, Ternullo and Zuccarello
presented the preliminary works on this topic and the results obtained during THEMIS
observing Campaign 2001 and 2002 [98, 121].
2.1.6
Sunspots rotation
Zappalà and Zuccarello used the ”age selection methodology” (ASM) to study the variability of the sunspot groups angular velocity during the activity cycle. The ASM is able
to separate the contribution of Young Sunspot Groups (YSG) from that of Recurrent ones
(RSG) in the Ω(θ) determination and therefore to evaluate whether the increase in angular
velocity during minima (reported in literature using all sunspot groups as tracers), is due
to a greater statistical weight of YSG on RSG or whether it reflects a global characteristic of the Sun. The results obtained from the analysis of sunspot groups data collected
during the period 1874-1981 (Greenwich Photoheliographic Results) indicate that during
minima, besides the fact that the percentage of RSG drops to ≤ 5%, both YSG and RSG
show the same increase in angular velocity, i.e. 0.16 degrees/day. Comparing these results
with those reported in literature and taking into account the internal angular velocity as
deduced by p-mode oscillations, it is possible to conclude that the observed higher angular
velocity of the Sun during minima concerns several layers of the Sun [92, 127].
2.1.7
Internal structure and dynamics
M. P. Di Mauro and co-investigators have concentrated on the use of the method of
helioseismic inversions in the attempt to restore the properties of the solar structure in
the near-surface region and to provide detailed tests for the equation of state and constrain
the envelope helium abundance.
In fact, the detailed structure of the convection zone and of the near-surface region is
still quite uncertain, since there remains substantial ambiguity associated with modelling
the convective flux, explaining the excitation and damping of the solar oscillations, defining an appropriate equation of state to describe the thermodynamic properties of the solar
structure, as well as in the treatment of non-adiabatic effects on the oscillations. In most
cases, in fact, the theoretical frequencies are calculated in the adiabatic approximation,
14
CHAPTER 2. RESEARCH
which is certainly inadequate in the near-surface region, where the thermal time scale
becomes comparable with the oscillation period.
Helioseismic inversions of new precise observations of modes with high harmonic degree
(l < 1000) obtained from the MDI instrument on the SOHO satellite together with the
use of a new suitable procedure to be adopted in the helioseismic inversions of high-degree
modes have allowed Di Mauro to obtain precise and well-resolved inferences in the subsurface layers through the HeII ionization zone and also part of the HeI ionization zone.
In order to suppress the uncertainties in the treatment of the surface layers in helioseismic
inversion procedures, they introduced the use of a new surface term, developed on the
basis of higher-order asymptotic theory of acoustic modes and suitable for the handling
of high-degree mode frequencies [14].
Their results have shown that the structure of the near-surface region of the solar
model is still a serious concern. In fact, below the photosphere, high-degree modes reveal
that there is still a large discrepancy between the model and the observed Sun. Moreover,
Figure 2.3: The intrinsic difference in the adiabatic exponent Γ1 between the Sun and
the OPAL (Rogers et al. 1996) equation of state (filled circle) and the Sun and the MHD
(Mihalas et al. 1988) equation of state (open triangles), in the sense (Sun) - (model),
obtained by inversion of a set of data by Rhodes et al. (1998), which includes high-degree
modes, and by considering the new surface term in order to suppress the uncertainties
in the treatment of the surface layers in helioseismic inversion procedures, . The vertical
errors are 2 σ propagated errors, while the horizontal bars give a measure of the localization
of the averaging kernels.
as it is shown in Fig. 2.3, they found evidence that the OPAL equation of state is able to
describe better the plasma conditions in the interior of the Sun below 0.97 R , whereas the
MHD equation of state gives a more accurate description than does the OPAL equation
of state in the layers within 0.97 R ≤ r ≤ 0.99 R , while above 0.99 R the differences
become very small and the two equations of state can be considered comparable.
Di Mauro used the same method to provide an estimation of the solar helium abundance in the envelope. The determination of the solar helium abundance by means of
helioseimic inversions is directly dependent on the equation of state employed in the reference model. By using the MHD equation of state, Di Mauro et al. (2002) obtained a
2.1. SOLAR PHYSICS
15
value of the helioseismic helium abundance in the convection zone Ye = 0.2457 ± 0.0005 ,
consistent within errors with the earlier results. By considering the OPAL equation of
state they obtain a value of Ye = 0.2539 ± 0.0005 , in quite good agreement or just slightly
higher than the earlier findings [14, 67].
A. Bonanno, in collaboration with H. Schlattl, and L. Paterno, showed that the inclusion of special relativistic corrections in the revised OPAL and MHD equations of state
has a significant impact on the helioseismic determination of the solar age, leading to a
remarkably good agreement with the meteoritic value for the solar age [7].
2.1.8
Dynamo theory of solar activity
In collaboration, with G. Rüdiger and D. Elstner, AIP, Potsdam, and G. Belvedere, A.
Bonanno has developed a high-precision code which solves the kinematic dynamo problem
both for given rotation law and meridional flow in the case of a low eddy diffusivity. It
has been shown that with a positive α-effect concentrated at the bottom of the convection zone, the role of the meridional circulation is crucial in determining the parity of the
solution, the form of the butterfly diagram and the phase relationship of the resulting
field components [8].
2.1.9
The 3rd Italian Solar Research Meeting
The meeting, held in the beautiful island of Vulcano of the Eolian archipelago from
September 30th to October 4th 2002 (see Fig. 2.4), is the third one on the Italian Solar
Research and follows the successful previous two, which were held in Rome in 1998 and
L’Aquila in 2000.
The number of participants increased steadily from the first meeting to this one, with a
large presence of young scientists, demonstrating the vitality of the solar research in Italy
validly projected in the international framework, in spite of the dark predictions about
its end in use some decades ago among the astronomical community. The renaissance of
the solar physics in these last fifteen years, which coincided with a renewed interest of the
young scientists in its study, certainly reflects the successes of the space missions devoted
to the study of the Sun, the extraordinary discoveries of the helioseismology, and more
recently the opening of the very promising field on the Sun-Earth relationships, called
space-weather in modern times.
The meeting, mainly sponsored by the Catania Astrophysical Observatory of the National Institute for Astrophysics, the Department of Physics and Astronomy and the Faculty of Sciences of the Catania University, was attended by 73 participants who contributed with 63 articles published in the Memorie della Società Astronomica Italiana,
among which there is a limited number of invited review articles to focus the most important problems in the various aspects of the solar research.
The five days of the meeting were devoted for discussing, in an informal and friendly
atmosphere, the most recent problems concerning the interior of the Sun, its atmosphere,
the magnetic activity, heating of chromosphere and corona, solar wind and interplanetary
16
CHAPTER 2. RESEARCH
Figure 2.4: Poster of the The 3rd Italian Solar Research Meeting
space, space-weather, climate global changes, instrumentation, archives, and the future
solar space missions.
At its opening, the meeting enjoyed a simple ceremony for celebrating two events, the
retirement of Giovanni Godoli and the 70th birthday of Giancarlo Noci. Both scientists
have significantly contributed to the development of solar physics in Italy and played an
important role as teachers and guides for the young solar physicists in Italy. A few words
for illustrating the career, scientific work and the human aspects of Giovanni Godoli were
said by Marcello Rodonò, Santo Catalano and Lucio Paternò, while Giannina Poletto did
the same for Giancarlo Noci. Two memorial silver plates were offered by the LOC to the
two honoured scientists.
More information on the meeting is available through the web page at:
http://web.ct.astro.it/eolian-2002/
2.2
2.2.1
Stellar physics
Magnetic activity and variability
INAF Researchers:
I. Busà, S. Catalano, G. Catanzaro, G. Cutispoto, A. Frasca,
A. F. Lanza, F. Leone, G. Leto, E. Marilli, S. Messina,
I. Pagano
University Researchers: G. Belvedere, A. C. Lanzafame, M. Rodonò
IRA Researchers:
C. Buemi, P. Leto, C. Trigilio, G. Umana
PhD Students:
K. Biazzo
Fellow:
G. Marino
2.2. STELLAR PHYSICS
2.2.1.1
17
Structure and modelling of the stellar chromospheres and coronae
Busà has worked on the study of physical and thermodynamic structure of the atmosphere,
from the photosphere up to the mechanically heated layers of the chromosphere, for
selected target stars representing different levels of stellar activity. In collaboration with
a group in Naples, she has worked on the NLTE modelling of radiative transfer, including
line-blanketing, and investigated the diagnostic power of spectroscopic lines such as the
Ca IRT triplet and the Na I doublet. To this purpose, high-resolution spectroscopic
observations of a sample of 40 late-type stars, spanning from basal to the highest level
of activity, have been obtained at Telescopio Nazionale Galileo by means of the SARG
spectrograph [112, 93].
A. Lanzafame, in collaboration with colleagues of the University of Strathclyde, Rutherford Appleton Laboratory and Goddard Space Flight Center, investigated spectroscopic
diagnostics for the solar transition region and corona finding also interesting results for
the analysis of stellar coronae. In particular, it is shown that a spurious multiple peak in
the DEM distribution between log(Te ) = 6.1 and 6.7, where Te is the electron temperature, may derive from an inaccurate treatment of the population densities of the excited
levels and ionisation fractions or from using an integral inversion technique with arbitrary
smoothing. Therefore, complex DEM structures, like those proposed for solar and stellar
coronae by several authors, must be considered with caution [19].
Pagano, in collaboration with J. Linsky of JILA and University of Colorado and other
colleagues has obtained and analysed high resolution echelle spectra of α Centauri by
means of the STIS spectrograph on board of the Hubble Space Telescope, deriving information on the upper chromosphere of this interesting solar-like star [75].
2.2.1.2
Magnetic structures in the photospheres, chromospheres and coronae
of single stars and close binary systems
Mapping of the atmospheric inhomogeneities of HR 1099. Messina, Lanza and Rodonò
have collaborated to a multiwavelength study of the RS CVn binary HR 1099 (V711 Tau).
Simultaneous and continuous observations of Hα, Hβ, He i D3 , Na i D1 ,D2 doublet and the
Ca ii H & K lines have been performed. The spectroscopic observations were obtained
during the MUSICOS 1998 campaign involving several observatories and instruments,
both echelle and long-slit spectrographs. During this campaign, HR 1099 was observed
almost continuously for more than 8 orbits of 2.8 days each. Two large optical flares were
observed, both showing an increase in the emission of Hα, Ca ii H & K, Hβ and He i D3
and a strong filling-in of the Na i D1 ,D2 doublet (Fig. 2.5). Contemporary photometric
observations were carried out with the robotic telescopes APT-80 of Catania and Phoenix25 of Fairborn Observatories. Maps of the distribution of the spotted regions on the
photosphere of the binary components were derived by using the Maximum Entropy and
Tikhonov regulatization criteria (Fig. 2.6). Rotational modulation was observed in Hα
and He i D3 in anti-correlation with the photometric light curves. Both flares took place
at the same binary phase (0.85), suggesting these events took place in the same active
region. Simultaneous X-ray observations, performed by ASM on board RXTE, show
several flare-like events, some of which correlate well with the observed optical flares.
Rotational modulation in the X-ray light curve has been detected with minimum flux
when the less active G5V star is in front. A possible periodicity in the X-ray flare-like
events was also found [42].
18
CHAPTER 2. RESEARCH
Figure 2.5: The observed line profiles of Hα (left panel), He i D3 , and Na i D1 ,D2 doublet
(middle panel), Hβ (upper right panel) and Ca II h&k (lower right panel) of the first
monitored flare on HR 1099 starting at JD 2451145.51, arranged in order of increasing
orbital phase from bottom to top.
Measurement of starspot temperatures. It has been recently proven by Gray and collaborators that line-depth ratios (LDR) are a powerful tool for temperature discrimination,
capable of resolving differences ≤ 10 K. In the hypothesis that in slowly-rotating stars the
passage of dark spots produces modulation of the center line depth of different amount in
lines of different sensitivity to temperature, S. Catalano, Biazzo, Frasca and Marilli have
made test observations on three active binaries of RS CVn type. Based on observations
made at Catania Astrophysical Observatory at a resolution R = 14 000, they have shown
that line-depth ratios can be effectively used to determine spot temperatures of active
binary systems. LDRs of ten line pairs, selected in the 6100–6300 Å wavelength range,
converted to temperature through the calibration relations derived from observations of
about 30 main sequence and giant stars, have led to clear rotational modulation of the
average surface temperature with amplitudes of 177 K, 119 K, and 127 K for VY Ari,
IM Peg and HK Lac, respectively, with an average estimated error of about 10 K. They
have shown that:
• the observed temperature variation amplitude allows us to define a minimum fractional spotted area coverage as a function of spot-photosphere temperature ratio
[11].
• the average spot temperature corresponding to the minimum spot coverage, although not univocally constrained, lead to temperature difference in good agreement
with values derived with other methods [11];
• the sharp rotational modulation of the average surface temperature is well correlated
to the simultaneous V light curves obtained by G. Cutispoto, S. Messina and M.
19
Figure 2.6: Top panel: V-band light curve (filled dots) of HR 1099 in 1998.89 fitted by
the Maximum Entropy spot model (continuous line). The flux was normalized to the
brightest magnitude (Vunsp = 5.744 at phase=0.21). The residuals (∆F/F ) between the
observed and synthetized light curves are also plotted vs. phase. Bottom panel: Maps of
the distribution of the spot filling factors at five rotation phases (equator-on orthographic
projection). Spots located at latitude below −33◦ cannot contribute to the flux because
the inclination of the star’s rotation axis is 33◦ .
Rodonó with the APT telescope [56], see Fig. 2.7);
• for each star, a unique solution for spot coverage and spot temperature can be
derived by an analytical approach on both temperature and light curve amplitudes
as shown in Fig. 2.8 and reported in Table 2.1 [56];
• the values of Tsp /Tph found for these three active stars are more compatible with a
weighted average of umbra and penumbra temperatures of solar spots [56].
Spatial association of spots and plages. The study of spatial association of spots and
plages in active binary systems has been continued by S. Catalano, Frasca and Marilli
by means of contemporaneous spectroscopic Hα and photometric observations. Spectroscopic observations were carried out with the REOSC spectrograph at this Observatory
in the spectral range 5860–6700 Å, while photometry have been obtained in various collaborations.
20
CHAPTER 2. RESEARCH
Figure 2.7: Upper panel: average effective temperature as a function of rotational phase
for VY Ari. Lower panel: simultaneous light curve.
Figure 2.8: Grids of solutions for the temperature (squares) and light curve (dots) amplitudes for VY Ari.
21
Combining photometric observations obtained at the Ege University Observatory (Tr)
and Hα, performed in summer 2000 on the system RT Lac, rotational modulation of the
Hα emission has been detected in both components [15]. However, while the Hα emission
of the more active G5 IV star is brighter over the hemisphere where starspots are mainly
located suggesting a close spatial association of spots and plages in this star, the reverse
is found for the cooler less massive G9 IV star.
Within the same collaboration, the binary system with solar-type components ER Vul
has been studied [36]. The net Hα equivalent width, arising from both components,
shows a phase-dependent variation. By deconvolving the Hα emission contributions, they
show that the more active component at the epoch of the observation is the secondary
one, and that this latter is also responsible for the rotational modulation of Hα emission,
interpreted as due to chromospheric plages.
Results on the systematic annual Hα and photometric observations obtained at Catania Astrophysical Observatory from 1989 to 1997 for HK Lac have been reported. Hα
excess-emission, evaluated with the spectral synthesis method, appear in all cases anticorrelated with the V band light curves. From model solutions of light curve obtained in
the hypothesis of circular spots the usual parameters Ts /T∗ , RS , ϕ and λ for the dark spots
have been derived, where ϕ and λ are the latitude and the longitude of the center of the
spot of radius RS , respectively. For modelling the Hα emission equivalent width (EWHα )
curve, bright spots were considered, assuming the emission flux ratio (Fplage /Fchrom ) between plage and quiet chromosphere as a free parameter [106].
Longitude differences (λspot − λplage ) between spot and plages do show a systematic
change from the most positive value of +40◦ in 1989 to the most negative value of −80◦ in
1997 (see Fig. 2.9). The authors remark that the change does occur in correspondence of
the maximum spot coverage between 1990 and 1992, as displayed by Oláh et al. (1997).
Although not definitely proven, it has been suggested that the change in longitude
difference may be associated with the change of magnetic field structure with the activity
cycle.
2.2.1.3
Systematic observations and activity cycles
Messina in collaboration with Rodonò and Cutispoto [39, 118] has continued the systematic search for starspots cycles initiated in late 1992 at the M.G. Fracastoro mountain
station with the 80-cm robotic telescope (APT80/1, see sect. 4.9).
The APT80/1 has been entirely devoted to the monitoring of a selected sample of
almost fifty known or suspected chromospherically active stars (see Table 2.2). The pho-
Table 2.1: Parameters obtained from analytical solutions.
Parameter
Tsp /Tph
Tsp (K)
∆T (K)
Arel
HK Lac
IM Peg
VY Ari
0.795
3788
977
0.38
0.845
3943
723
0.36
0.815
4007
909
0.45
22
CHAPTER 2. RESEARCH
Figure 2.9: Longitude shifts between spots and plages for HK Lac. The two vertical
dashed bars mark the time interval during which the minimum average brightness has
been observed.
tometry collected by the APT80/1, supplemented with previous archive data of the Observatory and other observatories, has allowed to obtain the most extended observation
database (up to more then 30 years) for several stars, e.g. BY Dra (Fig. 2.10) and V711
Tau (Fig. 2.11), which will enable to address questions concerning activity cycles, active
longitudes and surface differential rotation.
Lanza, S. Catalano and Rodonò, in collaboration with Ibanoglu, Evren, Tas, Cakirli
and Devlen (Ege University Observatory, Bornova, Izmir), analysed a sequence of V-band
year
BY Dra
V magnitude
8.0
8.2
8.4
8.6
10000
12000
14000
16000
18000
Heliocentric Julian Day (-2430000)
20000
22000
Figure 2.10: V-band photometry of BY Dra. Vertical bars are data from the literature,
while dots are our robotic observations. The amplitude of the vertical bars, as well as the
scatter in the dots at any epoch represent the peak-to-peak light curve amplitude, which
is due to the presence of photospheric spots whose visibility is modulated by the stellar
rotation.
23
Table 2.2: APT80/1 target stars
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
8357
8358
9902
12545
17433
20629
21242
21845
22403
22468
26337
32008
37394
37824
52452
65626
86590
106225
106677
107146
108102
112313
AR Psc
BI Cet
BG Psc
XX Tri
VY Ari
XX Ari
UX Ari
V577 Per
V837 Tau
V711 Tau
EI Eri
63 Eri
V1149 Ori
AE Lyn
DH Leo
HU Vir
DK Dra
IL Com
IN Com
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
HD
114519
116204
116544
117555
119213
134319
136901
143271
143313
144110
150708
160538
166181
167605
170527
171488
175742
179094
184398
199178
200391
RS CVn
BM CVn
IN Vir
FK Com
CQ UMa
IU Dra
UV CrB
MS Ser
EV Dra
WW Dra
DR Dra
V815 Her
V889 Her
V775 Her
V1762 Cyg
V1817 Cyg
V1794 Cyg
ER Vul
HD 209813
HD 210334
HD 216489
HD 218738
HD 219113
HD 224085
HD 234601
HD 234677
HD 250810
HD 283750
HD 337518
HD 341475
SAO 91772
SAO 130113
BD+16 516
BD+16 4908
BD+20 2465
BD+43 4305
BD+48 3686
BD+49 2392
BD+61 1211
HK Lac
AR Lac
IM Peg
KZ And
SZ Psc
II Peg
BY Dra
CQ Aur
V833 Tau
V511 Lyr
MM Her
LN Peg
BY Cet
V471 Tau
AD Leo
EV Lac
V383 Lac
DM UMa
year
5.50
5.60
V711 Tau
V magnitude
5.70
5.80
5.90
6.00
4000
6000
8000
10000
Heliocentric Julian Day (-2440000)
12000
Figure 2.11: The same as in Fig. 2.10 but for V711 Tau.
light curves of the active close binary RT Lacertae (G5+G9 IV), extending from 1965
to 2000, to derive the spot distribution and evolution on the component stars. In the
modelling approach, as implemented in a computer code written by Lanza and Rodonò,
the Roche geometry and Kurucz’s atmospheric models were adopted. The resulting maps
24
CHAPTER 2. RESEARCH
of the spot surface distribution were regularized by means of the Maximum Entropy and
Tikhonov criteria to take full advantage of the increased geometrical resolution during
eclipses. By comparing the maps obtained with these two criteria, it was possible to
discriminate between surface features actually required by the data and artifacts introduced by the regularization process. Satisfactory fits were obtained assuming spots on
both components and the unspotted V-band luminosity ratio: LG5 /LG9 IV = 0.65 ± 0.05.
The more massive G5 primary appears to be the most active star in the system and its
spotted areas are mainly responsible for the light curve distortions. The yearly spot distributions on both components indicate that their spot patterns consist of two components,
one uniformly and the other non-uniformly distributed in longitude, the latter suggesting
the presence of preferential longitudes. In particular, spots are concentrated around the
substellar points and their antipodes on both stars. The eclipse scanning reveals spots
with diameters of ∼ 40◦ , or possibly smaller, on the hemisphere of the primary star being
occulted. The primary shows clear evidence for a short-term activity cycle with a period
of 8.5 yr and a possible long-term cycle with a period of approximately 35 yr. The
variation of the spot migration rate may be related with surface differential rotation, with
a lower limit of ∆Ω/Ω ∼ 3.2 × 10−3 . The G9 IV secondary does not show evidence for an
activity cycle, its spot coverage appearing rather constant at 15-20% of its surface. The
relative amplitude of its surface differential rotation, as indicated by the variation of the
spot migration rate, is ∆Ω/Ω ∼ 2.7 × 10−3 [18].
2.2.1.4
Orbital period modulation and magnetic activity cycle in close binaries
The recent analysis of the long-term activity of RT Lac by Lanza, S. Catalano, Rodonò and
collaborators shows that the variation of the orbital period is correlated with the activity
level of the primary component (cf. Fig. 2.12. Specifically, the decreases of the orbital
period appear to be associated with minimum spottedness and sizeable changes of the
surface spot distribution that may be related to increases of the rotation rate of the spot
pattern. Conversely, an episode of increase of the orbital period was related to an increase
of the spotted area on the primary star. Such results support the recently proposed models
that connect the perturbations of the orbital dynamics with the variation of the figure of
equilibrium of the active components, due to the operation of non-linear hydromagnetic
dynamos in their extended convective envelopes [18] . The principal characteristics of
the observed orbital period variation in magnetically active close binaries were briefly
reviewed and the theoretical models proposed to interpret them were presented by Lanza
and Rodonò. In particular, they focussed on the models proposed by Applegate (1992)
and Lanza, Rodonò & Rosner (1998) to explain the short-term modulation of the orbital
period, as a consequence of the changes of the gravitational quadrupole moment of the
active component driven by a cyclic hydromagnetic dynamo. Recent observational results
supporting this interpretation and the constraints on the intensity of the internal magnetic
fields that are required by the proposed mechanism were discussed. A novel, stringent
test of Applegate’s model based on future asteroseismic space observations of oscillation
mode splitting, was also briefly presented [59, 17].
25
Figure 2.12: a) The total spot area A (average between ME and T models) of the primary
star in RT Lac, b) the longitude of the centroid of its spot pattern Lc and c) the O − C
diagram vs. time. The four intervals of approximately constant orbital period described
in the text are indicated in panel c) and the times of orbital period changes are marked
by the dotted vertical lines. The long-dashed lines in panel c) are linear best fits to the
O − C points during intervals of approximately constant orbital period.
2.2.1.5
Evolution of stellar magnetic activity and related phenomena
”The Sun in time” project. Messina in collaboration with Guinan (Villanova University,
PA/USA) continues to carry out a multi-wavelength study of solar analogues with ages
∼ 100 million years to 9 billion years as part of The Sun in Time project. The data
for this program are obtained with NASA and ESA satellites such as ASCA, ROSAT,
XMM, Chandra, EUVE, FUSE, IUE and HST. Also, observations of most of these stars
are being made with Villanova’s 0.8 meter robotic telescope (FCAPT) in Arizona. The
main scientific goals are (a) to study the solar magnetic dynamo (with rotation as the only
variable) and (b) to determine the radiative and magnetic properties of the young Sun
with the purpose of constructing irradiance tables to be used to study paleo-planetary
atmospheres.
Messina and Guinan [20] have analysed the long-term V-band photometry collected
since 1990 as part of the project for a subsample of five young single G0-G5V stars with
ages between ' 130 Myr and 700 Myr: EK Dra, π 1 UMa, HN Peg, k1 Cet and BE
Cet. Also they include in this study the Pleiades-age (' 130 Myr) K0V star DX Leo
(HD 82443).
Messina and Guinan found the existence of prominent activity cycles which are the
first determined from photometric data (Figs. 2.13-2.14) for all the cited stars. The
26
CHAPTER 2. RESEARCH
starspot cycles are compared to those activity cycles derived from CaII H&K emission
fluxes and differences are discussed. All the cycle periods, except for EK Dra, fit well the
empirical relations with global stellar parameters derived from larger stellar samples. The
correlations of the starspot amplitude and frequency (ωcyc ) with age and Rossby number
(R0 ) are investigated.
The following results are also inferred from the present study: i) the fastest rotating
stars tend to have longer cycles; ii) the range in the observed cycle lengths seems to converge with stellar age from a maximum dispersion around the Pleiades’ age towards the
solar cycle value at the Sun’s age; iii) the overall short- and long-term photometric variability increases with inverse Rossby number with very high correlation degree, indicating
that the level of magnetic activity at least in photosphere is still controlled by the stellar
rotation even on the longest time scales (see left panel of Fig. 2.15); iv) the increase with
inverse Rossby number of the long-term overall photometric variability seems to level off
at the highest rotation rate, which may be interpreted as due to a saturation in the level of
photospheric magnetic activity around the activity maximum. v) In a ωcyc -R0−1 diagram,
in agreement to what found in analogues studies, the stars tend to dispose along three
different branches: inactive, active and superactive (see right panel of Fig. 2.15).
year
1988
6.95
1990
1992
1994
1996
DX Leo
1998
2000
Pcyc= 3.21 (yr)
V magnitude
7.00
7.05
7.10
7.15
7.20
7000
8000
9000
10000
HJD - 2440000
11000
12000
Figure 2.13: Time sequence of V-band magnitudes of DX Leo. Continuous line is a
sinusoidal fit to the data with a period Pcyc = 3.21 ± 0.05 (yr). Open diamonds are the
mean magnitudes computed from individual light curves (Vmax +Vmin )/2 and used in the
periodogram analysis.
Lithium abundance versus age and magnetic activity level. It is still not clear if the
large spread of Li abundances observed in both clusters and field stars reflects a genuine
dispersion of abundances or if it is due to phenomena linked to stellar magnetic activity.
Cutispoto discussed observational and theoretical results on Li abundance and concluded
that, although activity alone does not seem able to account for the spread observed in
27
year
1985
1990
1995
2000
7.40
EK Dra
P cyc 1= 9.2 (yr)
P cyc 2= >30 (yr)
V magnitude
7.50
7.60
7.70
7.80
6000
7000
8000
9000
10000
HJD - 2440000
11000
12000
Figure 2.14: Time sequence of V-band magnitudes of EK Dra. Continuous line is a
sinusoidal fit to the data with a period Pcyc = 9.2 ± 0.4 (yr) plus a linear long-term trend,
which in the case of a cycle would be longer than 30 years. Open diamonds have same
the meaning as in Fig. 2.13.
Li abundances, it is, at least for late type stars, unsafe to assume that the spread is
entirely due to genuine Li depletion [57]. He also analyzed recent data on Be abundance
measurements in old clusters, that can shed further light on the activity vs. light elements
abundances relationships.
In low-mass main sequence stars, internal structure is determined primarily by stellar
mass rather than age. In contrast, surface activity as manifested in X–rays, at least for
late-type dwarfs, seems to scale directly with rotation and by consequence with age, but
is only slightly dependent on mass. Cutispoto and collaborators presented an analysis of
high-resolution spectroscopic and high-precision UBV(RI)c photometric observations of a
sample of 110 nearby late-F and G-type stars selected for their large rotational velocity.
They investigated the relationships between Li abundance, X–ray luminosity, and v sin i.
They find that, as expected, the stars in the selected sample show statistically higher
Li abundance and activity level than field star samples with similar characteristics, but
slower rotation. Surprisingly, however, they also find four rapidly-rotating single mainsequence stars with very low Li abundance. For both single and binary stars they find
a large spread of Li abundance for stars with rotation lower than about 18 km s−1 The
well-established correlation between X-ray luminosity and rotation rate is clearly observed.
All single unevolved solar-type stars with v sin i larger than 18 km s−1 are strong X-ray
emitters and have high Li abundance. Finally, they find also five evolved stars with very
low Li abundance that are still rather fast rotators [13, 132]. These results confirm the
presence of young very active stars close to the Sun, in agreement with recent findings
from EUV and X–ray surveys, although the studied sample does not show such extreme
characteristics as those selected from EUV and X–ray surveys at the current flux limits
28
CHAPTER 2. RESEARCH
Figure 2.15: Left panel: The amplitude of the overall V-band variability is plotted vs.
log(R−1
0 ). Continuous line represents a cubic fit to the data. The amplitude is computed
as the difference between the brightest and faintest observed magnitudes. In the case
of EK Dra (D) the filled dot denotes cycle amplitude only, while the asterisk denotes
cycle amplitude plus longer-term trend. Right panel: Log(ωcyc /Ω) vs. log(R−1
0 ) for the
program stars. The cycles of LQ Hya (G), AB Dor (H) and the Sun are also plotted.
Different stellar ages are indicated by different symbols, while each target is identified by
the corresponding label as reported in Table 1 of [22]. Smaller symbols denote secondary
cycles. Lines are the least-squares fits from Saar & Brandenburg (1999).
[13, 40].
2.2.1.6
Dynamo theory of stellar magnetic activity
Paternò, Belvedere, Kuzanyan (IZMIRAN, Solar-Terrestrial Dept., Moscow) and Lanza
investigated the behaviour of a simple thin-shell αΩ dynamo model in the asymptotic
regime, i.e., characterized by dynamo numbers much larger than the critical one, in order
to derive scaling relationships connecting the properties of dynamo waves with global
stellar parameters. The proposed approach was applied to stellar models of subgiant and
giant stars from K0IV to K1III spectral types in the Hertzsprung-Russell diagram, to
predict some characteristics of activity cycles in very active stars. They found that the
strength of the dynamo action in such stars is higher than in the Sun. Therefore, larger
magnetic field energy and larger spot filling factors were expected, in agreement with
observations. The periods of stellar cycles were also estimated and compared with observations. The characteristic times of migration of the starspot belts relative to the cycle
period, namely the Hale number, together with the ratio of toroidal to poloidal dynamo
magnetic fields, were estimated. From their simplified analysis, they could only derive
general trends, but could not perform a direct comparison with the observed properties
of particular active stars. These general trends indicate that the cycle periods have a
large spread for stars with low rotation rates (∼ 1 − 5 times the solar one), while they
tend to be saturated for stars with high rotation rates (∼ 5 − 15 times solar), for which
the periods range from 10 to 20 yr. For such stars, Hale numbers ranged from 1.5 to
approximately 4 (the Hale number for the Sun is approximately 1.1), denoting the pos-
29
sible existence of cycles with different periodicities present simultaneously. The ratio of
toroidal to poloidal dynamo fields tended to become smaller for increasing rotation rates,
indicating a transition from the αΩ to the α2 Ω type of dynamo. Moreover, the magnetic
field filling factors tended to become larger for faster rotation rates, though the effect of
the convection zone depth should not be neglected. Their results showed a reasonable
agreement with available observations of a sample of active stars they considered [22].
Rüdiger, Elstner (AIP, Potsdam), Lanza and Granzer (also from AIP) faced the question concerning whether dynamo-generated magnetic fields are able to produce such
quadrupole terms in the gravitational potential which can explain the observed cyclic
orbital variation of RS CVn stars. They started with spherical dynamo models with
outer convection zones but without any differential rotation, i.e. with α 2 -dynamos which
are known as nonoscillating. With the known anisotropic α-tensor of rapidly rotating
stars the magnetic modes with the lowest dynamo numbers are nonaxisymmetric with a
slow azimuthal drift. They also found, however, stable (i.e. with the lowest dynamo number) axisymmetric oscillating modes but only for a very special, highly inhomogeneous
α-tensor. The dynamo model was a linear one with an arbitrary field amplitude which
could be scaled in order to reproduce the observations. The star proved to be as prolate
during the maximum of the toroidal field energy and it proved to be as oblate during the
maximum of the poloidal field energy. In the time average the influence of the toroidal
field dominated and the star is slightly prolate. From the computed temporal variations
of the gravitation quadrupole moment a magnetic field of more than 105 G is needed in
order to produce a period modulation of order 10−5 which has been observed [24].
G. Belvedere, in collaboration with Zaqarashvili and Javakhishvili (University of St.
Andrews, Scotland and the Abastumani Astrophysical Observatory, Tbilisi, Georgia) proposed a new model to explain the enhanced magnetic activity observed in tidally interacting binary systems. It is based on the assumption that a torsional Alfven wave may
be excited and amplified inside the active component by means of a parametric resonance
mechanism. Specifically, they suppose that the deviation of the active component from
spherical symmetry due to the tidal influence of the companion leads to stellar pulsation in
its fundamental mode. It is shown that stellar radial pulsation amplifies torsional Alfven
waves in a dipole-like magnetic field, buried in the interior, according to the recently
proposed swing wave-wave interaction. Then amplified Alfven waves lead to the onset of
large-scale torsional oscillations, and magnetic flux tubes arising toward the surface, owing to magnetic buoyancy, diffuse into the atmosphere producing enhanced chromospheric
and coronal emission [29].
2.2.1.7
Space projects to study stellar activity and variability
The researchers in Catania are involved in the design phase and development of several
space projects to study the atmospheres of magnetically active stars in UV and optical
bands. Moreover ground based monitoring of some of the targets of the asteroseismology
program of the space mission COROT is performed using the telescopes at the M.G.
Fracastoro mountain station (see 3.1).
30
2.2.2
CHAPTER 2. RESEARCH
Stellar oscillations and asteroseismology
INAF Researchers:
A. Bonanno, M. P. Di Mauro, A. Frasca, A. F. Lanza,
R. Ventura
University Researchers: L. Paternó, M. Rodonò
Student:
G. Mignemi
In a review paper, Paternò, Di Mauro and Ventura examined the present status of the
asteroseismology, developed in recent years along the guidelines of its mother discipline,
the helioseismology. After an introductory history about solar and stellar small amplitude
oscillations, the authors recall the basic physics of stellar pulsations and how these can
be used to infer the structural and dynamical properties of the Sun and stars. In the
framework of their location in the HR-diagram, the authors deal with the several classes of
small amplitude pulsators useful for asteroseismic studies. The methodologies concerning
the pulsation data inversion, namely the methods for deducing the internal structure and
dynamics of the stars from their oscillation spectra, are illustrated with application to the
Sun and stars [61].
A major activity of the stellar oscillation group during the year has been the investigation of stars suitable for seismological analysis which has been selected as primary
science targets for ground-based observational campaigns or for upcoming space missions.
In order to assess the information that is and will be available from such observations, Di
Mauro in collaboration with L. Paternò (University of Catania), J. Christensen-Dalsgaard
and A. Miglio of the University of Aarhus (DK), H. Kjeldsen and F. Pijpers of the TACAarhus (DK), M. J. Thompson of the Imperial College, London (UK), T. Bedding of the
University of Sydney and Mario J.P.F.G. Monteiro of the University of Porto (Portugal),
has developed a study on the properties of the internal structure of stars which show
solar-like pulsations which, similarly to those observed in the Sun, are believed to be
excited stochastically by turbulent convection.
One of the activities of Di Mauro in the team is the production of evolutive models by
using the evolution code of Christensen-Dalsgaard by adopting updated microphysics and
recent measuments of the observed basic parameters. The code can produce models which
include also diffusion of heavy elements and overshooting from the convective core during
the main-sequence phase. The structure models which match the observed properties
of the star considered are then selected for the calculation of the adiabatic oscillation
frequencies by using the Aarhus oscillation code.
In particular Di Mauro has considered theoretical investigation of the stars η Bootis
and of β Hydri.
The subgiant HR 5235, better known as η Bootis, is a well-studied bright star of
spectral type G0 IV, on which observations have recently confirmed the presence of solarlike oscillations with a spectrum characterized by a large frequency separation ∆ν =
(40.47±0.05) µHz and a small frequency separation δν = (3.06±0.14) µHz. The theoretical
calculations identifies η Boo as being in the post-main-sequence phase of evolution with
a mass in the range M = 1.64 − 1.75 M . It has a helium core, having exhausted its
central hydrogen, and it is in the shell-hydrogen-burning phase, evolving toward the red
giant branch. The models have a convective envelope extending from the base located at
about rcb ' 0.84R into the photosphere. Models which fit the position of η Boo in the
H-R diagram may have a maximum overshooting extent of `ov = 0.25Hp . Some of the
31
Figure 2.16: Evolutionary tracks for η Bootis plotted in an H-R diagram, calculated for
increasing values of the extension of overshooting from the convective stellar core. Models
are calculated with M = 1.7 M and assuming the observed metallicity (Z = 0.04).
The rectangle defines the one-sigma error box for the observed luminosity and effective
temperature of the star.
resulting evolutionary tracks plotted in an H-R diagram computed for η Bootis with and
without overshooting from the convective core are plotted in Fig. 2.16.
The comparison between theoretical and observed oscillation spectra indicates that
both models with and without convective-core overshooting can be constructed which are
consistent with the observed frequency separations.
The echelle diagram of Fig. 2.17 has been obtained for a model which does not
include overshooting. It shows that the frequencies calculated for l = 0 and l = 2
are consistent with observations (filled symbols). The model frequencies for modes with
l = 1 are strongly affected by avoided crossings and they deviate from the expected
asymptotical behaviour. From the study of Di Mauro et al. [41], it can be concluded
that the observations indicate two possible main evolutionary scenarios for η Boo: (i)
a more evolved star without core overshooting and whose oscillation spectrum contains
frequencies of nonradial modes with mixed character due to avoided crossings; (ii) a less
evolved star which includes overshooting from the convective core and has p modes in
the observed frequency range which show no mixed character and follow the asymptotic
theory. Intermediate cases are also possible as represented by a model which includes
modest convective overshooting from the core and with typical characteristics of both the
two above mentioned scenarios (see [41]).
The other target considered is HR2021, better known as β Hydri, a G2 IV subgiant
with a mass close to that of the Sun and for which observations have shown the presence of
solar-like oscillations. β Hydri is one of the best candidates for asteroseismic studies since
it is one of the better-observed individual stars other than the Sun, providing accurate
estimates of the basic parameters. β Hydri is in the post-main-sequence phase of its
evolution, with a helium core and a hydrogen-burning shell. The calculations have allowed
to establish that its mass is limited to the range (1.07 − 1.20) M , the age is about (5.2 −
6.1) Gyr and the radius is R ' 2 R . The theoretical models can reasonably reproduce the
32
CHAPTER 2. RESEARCH
Figure 2.17: Echelle diagram based on observed and computed frequencies for η Boo.
The filled symbols show observed frequencies while the open symbols show computed
frequencies for a model which neglects overshooting. Circles are used for modes with
l = 0, triangles for l = 1, squares for l = 2, diamonds for l = 3. The size of the open
symbols indicates the relative surface amplitude of oscillation of the modes. Crosses are
employed for modes with small predicted amplitude (e.g. g-modes).
observed spectrum. In particular, Di Mauro and collaborators found that the theoretical
large separation is about ∆ν ' (52 − 57) µHz, while the theoretical small separation is
about δν0 ' 5 µHz, values which are certainly consistent with the observed ones. However,
while the evolutionary scenario of β Hydri looks already quite well constrained, thanks
to the existing spectroscopic and photometric data, it is evident that only more accurate
asteroseismic observations will allow further investigation of the properties of the interior
of this star [102, 119].
Recently, Di Mauro and collaborators started to consider also structure models of
rapidly rotating stars, being able to include the effect of fast rotation in stellar modelling
and in the calculation of frequencies of global oscillations. In fact, the rotation remove
the frequency degeneracy in the azimuthal order m of the oscillation modes and may also
significantly modify the equilibrium structure and the evolution of a star.
The effect of rotation in the models has been taken into account by assuming for semplicity an uniform (solid-body) stellar rotation and including the spherically symmetric
component of the centrifugal acceleration in the equations for the stellar structure. The
effects of the rotation on global oscillations have been calculated by assuming that the
angular velocity inside the star is uniform, following a second-order perturbation approach
as described by Gough & Thompson (1999). In particular, such study has been applied
to two well-observed δ Scuti stars, namely V480 Tau and θ 2 Tau A, both members of the
Hyades open cluster [58, 103].
2.2.2.1
Asteroseismology of hot subdwarf stars
During a photometric campaign dedicated to the hot subdwarf B (sdB) stars, A. Bonanno,
Frasca, S. Catalano, Paternó and Mignemi discovered short period oscillations in PG
33
1613+426 from time-series photometry carried out with the 91-cm Cassegrain telescope.
This star, which is brighter than the average of the presently known sdB pulsators, with
B = 14.14 mag, has Teff = 34 400 K and log g = 5.97. Its position is near the hot end
of the sdB instability strip, and it is a pulsator with a well-observed peak in the power
spectrum at a period of 144.18±0.06 s. This star seems to be well-suited for high-precision
measurements, which could detect a possible multi-mode pulsation behaviour [35].
2.2.2.2
Orbital period modulation and oscillation in magnetically active close
binaries
Lanza and Rodonò re-visited the connection between magnetic activity and orbital period
modulation in RS CVn binaries in order to identify possible asteroseismic tests for models
that have been proposed to understand their relationship. These models were based on
the variation of the gravitational quadrupole moment of the active component, as a consequence of the modification of its internal rotation regime and magnetic field along its
activity cycle (Applegate 1992; Lanza et al. 1998). An analysis based on the solar analogy
showed that surface magnetic activity might produce shifts, splitting and broadening of
the p-mode peaks in the oscillation spectrum of a star. Such effects make the direct detection of the internal structural changes predicted by the models very difficult. However,
a time variation of the internal rotation can be detectable because the p-mode rotational
splittings are proportional to the azimuthal quantum number m, whereas structural and
surface effects controlled by the magnetic fields are expected to be |m| dependent. Therefore, Lanza and Rodonò proposed a method that correlates the variation of the a 1 splitting
coefficients, that sample the internal rotation, with the orbital period variation in order
to test the predictions of the models. An illustrative example of the expected changes
is shown is Fig. 2.18 for a model binary system consisting of two main-sequence stars of
mass 0.7 M on a 12-hr orbit, which represents a typical short-period RS CVn system.
Indeed, the RS CVn short-period systems, such as V 471 Tau, RT And or CG Cyg, were
found by Lanza and Rodonò to be the most suitable objects for such a test because surface
magnetic effects are likely to be less prominent than in classical or long-period RS CVn
binaries [17].
2.2.3
Chemical composition studies and chemically peculiar stars
INAF Researchers:
I. Busà, S. Catalano, G. Catanzaro, F. Leone
University Researchers: F. A. Catalano
IRA Researchers:
P. Leto
2.2.3.1
Extremely metal-poor stars
Busà is involved in the 0Z project (http://www.hs.uni-hamburg.de/DE/For/Gal/Met/0Z.html), a large observational program to find extremely metal poor stars with highdispersion abundance analyses with the aim of shedding light on the early epoch of the
formation of the Galaxy, the chemical evolution of the Galaxy, and related issues. This is
being accomplished by observing candidate stars from the Hamburg/ESO Survey (HES)
(which has a two times higher effective yield of extremely metal poor stars than the
existing HK survey) with Keck I/HIRES, and, starting in 2002, also with Magellan 1.
34
CHAPTER 2. RESEARCH
Figure 2.18: The variation of the splitting coefficients ∆a1 for three p-modes versus the
relative angular velocity change in the inner shell of the convection zone ∆Ωi /Ω0 . The
splitting coefficients refers to high-order modes with l = 1 (solid line), l = 2 (dashed
line) and l = 3 (dot-dashed line), respectively. The upper panel reports the results
for rs /R = 0.75, the middle one for rs /R = 0.80 and the lower one for rs /R = 0.85,
respectively, where rs is the radius at the boundary between the two shells partecipating
to the exchange of angular momentum during the cycle of activity and R is the radius of
the star. On the right scale, the relative change of the orbital period of the model binary
system considered by Lanza and Rodonò is reported.
Extremely metal-poor stars show a large star-to-star scatter in absolute abundances
as well as abundance ratios for a variety of elements, e.g., the neutron-capture elements
(e.g., McWilliam et al. 1995; Ryan et al. 1996). This phenomenon can most easily be explained in terms of local enrichment of the primordial ISM by a small number of exploding
massive stars (Audouze & Silk 1995). As the amount of newly synthesized elements often
show large variations with mass (or other parameters like rotation and metallicity) of the
exploding star, the abundances might have varied extensively throughout the Halo ISM.
Subsequent star formation then preserved these chemical inhomogeneities on the surfaces
of low-mass stars. Hence, studying these stars by statistical means, especially by displaying them in diagrams relating different abundance ratios (i.e. correlation diagrams),
should reveal interesting information on the production sites of the elements.
Simulations of the early, inhomogeneous Galactic halo (Karlsson & Gustafsson 2001)
show that the distributions of extremely metal-poor stars in correlation diagrams are insensitive to any other parameter than the supernova yields. Specific variations in the
yields produce certain stellar patterns in the diagrams. Thus, we can distinguish theoret-
35
ical yield calculations merely by studying the patterns. Furthermore, by quantitatively
comparing an observed pattern with simulations it should be possible to reconstruct supernova yield ratios, or even absolute yields assuming we have a reference element. A
large, homogeneously observed stellar sample is ideal for a such a quantitative, statistical
study.
Half of the elements heavier than iron were made in the r process. In the r-process
isotopes are formed very far away from the line of stability in a high neutron flux environment (probably the hot neutrino bubble of an SNII). If a thermal equilibrium situation
is reached, the abundances of isotopes depend simply on neutron separation energies
(nuclear masses) and half-lives.
We aim at identifying 10-15 new very metal-poor stars strongly enhanced in r-process
elements, in which thorium and uranium can be detected and which provide nucleochronometric age dating. We expect that 2-3 % of the halo stars with [Fe/H] < −2.5
display strong r-process enhancement.
2.2.3.2
Chemically peculiar stars
Chemical Peculiar (CP) stars of the Main Sequence show several characteristics that could
be summarized as: i) a non-standard chemical composition of their atmospheres and ii)
a variability that involves their luminosity, spectrum and magnetic field.
Chemical Abundances: Carbon. Carbon is one of the major constituents of a normal
stellar atmosphere and also one of the principal contributors to the metallicity of the
stellar material. It is also a probe to test different theories on diffusion processes involved
to explain the abundance anomalies observed in the various classes of CP stars.
The approaches used in literature to study the carbon abundance are sufficiently puzzling. Some authors carried out NLTE analysis to investigate the behavior of carbon lines
in standard main sequence stars, some others, on the contrary, based their deduction
exclusively on LTE calculations.
To overcome the difficulties arising from theoretical modelling, Catanzaro and Leone
analyzed the behavior of carbon in normal and peculiar stars, looking only at the equivalent widths of three important CII lines: λλ 4267, 6578 and 6582 Å. The data used for
this study have been collected at the CAT-ESO telescope equipped with the CES spectrograph (R = 60000) and at the 2.1-m telescope of the Complejo Astrònomico El Leoncito
(Argentina) equipped with a Boller and Chivens cassegrain spectrograph (R = 12000).
The equivalent widths measured in the peculiar stars have been compared with the values
measured in the normal stars of the same Teff .
The conclusion of this research was that the general trend of the carbon abundance
inferred by the equivalent widths of these spectral lines is close to the solar standard
value. However, a very large scatter from the normality has been observed in the case
of He-weak stars, that could be due to significant abundance differences from the solar
value, but no systematic differences have been observed [12].
HD 207538. In the attempt to study the chemical composition of stars, a very important
task is the modeling of their atmosphere. A good model is a fundamental starting point
for a detailed quantitative analysis of the chemical composition. Its importance is stressed
in the case of CP stars, for which the overabundances of metals change the structure of
36
CHAPTER 2. RESEARCH
their atmospheres.
The most reliable codes presently used for such purposes are the Kurucz’s ATLAS and
SYNTHE. These programs have been extensively and successfully used to model optical
spectra of stars whose spectral types lie between B and A.
With the advent of new instruments from space, new optical windows are opened
for researchers. Recently, Far-UV (namely wavelength shortward Lyα) high resolution
spectra become available thanks to the Far Ultraviolet Satellite Explorer (FUSE).
A new question arises: are the available codes able to reproduce the spectra observed at those wavelengths? To try to give an answer to this question, Catanzaro and
Leone, in collaboration with M. Andrè (Institute d’Astrophysique de Paris, France) and
P. Sonnentrucker (Johns Hopkins University, Baltimore, MD, USA), modelled the observed spectrum of HD 207538 (BO V) from far-UV to visible with a single set of stellar
parameters. They selected HD 207538 within their program dedicated to the study of
magnetic CP stars. An optical spectrum of this star has been obtained with the high
resolution spectrograph (SARG) at Telescopio Nazionale Galileo. UV and far-UV spectra
have been extracted from the IUE and FUSE archive respectively. ATLAS9 has been
used to compute the model of the atmosphere and SYNTHE to reproduce the observed
spectrum.
Because of the inter-stellar matter (ISM) present between the star and us, the FUSE
spectrum is strongly contamined by ISM spectral lines. Thus, they decided to perform
an abundance analysis of the ISM material toward the line of sight of HD 207538. The
ISM theoretical spectrum has been computed with the code OWENS developed by M.
Lemoine and the FUSE French team. This spectrum has been combined with the one
computed with SYNTHE and the result has been compared with the observations.
Figure 2.19: Comparison between theoretical and observed spectra in the FUV range
λλ 1000 - 1098 Å. In each panel we plotted at the top the ISM model (green line) with
labelled the identified lines, in the middle the synthetic photospheric model (blue line)
with the identified lines and at the bottom the observed spectrum compared with the
total model (red line).
37
Figure 2.20: Comparison between theoretical and observed spectra in the FUV range λλ
1098 - 1188 Å. Symbols as in Fig. 2.19.
Catanzaro, Leone and collaborators demonstrated that they could reproduce the observed spectrum of HD 207538, including also the ISM features, with a single set of atmospheric parameters (Teff = 32190 K, log g = 4.32 and ξ = 8 km s−1 ) and chemical abundances. Results of their modeling are showed from Figs 2.19, 2.20, 2.21, 2.22, 2.23.
As a by-product of their analysis, they ruled out the studied star from the CP group,
since any of the observational characteristics of CP stars have not been observed on it.
In particular, to check out if the star shows spectral variability, they collected some spectra at the Catania Astrophysical Observatory. No hints of variability have been found
(Catanzaro et al. 2003, submitted to A&A).
Stratification of the elements. With the aim of studying the possible vertical stratification of the chemical elements along their atmosphere, Catanzaro, Leone and M. André
performed spectroscopic observations of a sample of helium peculiar stars at 1.5-m ESO
telescope in La Silla (Chile) equipped with the FEROS spectrograph. Unfortunately, due
to bad weather conditions they could get spectra only for 6 out of the 30 stars scheduled.
In any case, these high resolution spectra (R = 48000) should be enough to allow a
preliminary analysis. This research is still in progress.
2.2.3.3
Spectral variability in chemically peculiar stars
Helium line variability. To try to understand the behavior of helium variability in CP
stars, Catanzaro and Leone continued their on-going observational campaign started two
years ago (Catanzaro et al., 1999). This year, they performed new time-resolved spectroscopic observations of the HeI5876 Å line for a sample of 10 stars in the spectral range B3
- A2, characterized by different overabundances. The observations have been performed
with the spectrograph of the 91-cm telescope of Catania Astrophysical Observatory.
In the scenario described by the Oblique Rotator Model spectroscopic, photometric
and magnetic data should vary with the same period. Since the work of Mihalas (1973),
38
CHAPTER 2. RESEARCH
Figure 2.21: Comparison between theoretical and observed spectra in the IUE range
selected (λλ 1380-1670 Å). In each panel we labelled the identified lines. ISM lines have
been marked with arrows.
the variability of the strength of helium lines has been explained by the presence of large
caps of such element placed around the magnetic poles. In such a way, the rotation of the
star is responsible of the observed spectral variability.
The principal aim of this kind of studies is to explore the phase relations among spectral, light and magnetic variations by searching for correlations with physical properties
of the stars such as spectral type or chemical peculiarities.
To pursuit their goal, Catanzaro and Leone searched in the literature for photometric
and magnetic measurements. Hipparcos photometric catalogue has been queried for light
curves. Data for all stars of the sample have been found, while for five of them they found
magnetic observations. As an example, the observed spectral variability for HD 124224
and HD 142990 are reported in Figs. 2.24, and 2.25
Thanks to this new data-set, Catanzaro and Leone explored the possible relations with
peculiarity classes and lengths of the rotational periods. They confirmed the conclusions
published previously (Catanzaro et al., 1999), that is: no-unique correlation exists and
this fact is independent of the Teff of observed stars, the peculiarity classes and the periods of variations. According with the estimated Teff and log g, they classified the program
stars with respect to their helium abundance; the results are reported in Fig. 2.26 [38].
HgMn in binary systems. Catanzaro and Leone continued their campaign devoted to the
study of the spectroscopic binary stars with a chemically peculiar component. To deal
with an homogeneous sample, they selected all the systems with a HgMn component. As
the name of the class implies, in the HgMn stars lines of both Mn and Hg are abnormally strong. In addition, lines of elements not seen at all in normal stars may be quite
prominent, such as those of gallium, platinum, phosphorus, xenon and krypton.
They selected 34 systems in total and for the 27 already observed they could calculate
orbital parameters. To address this aim, they wrote an IDL procedure that compute
39
Figure 2.22: Comparison between theoretical and observed spectra in the visible range λλ
4625-4720 Å (top panel) and λλ 5650 - 5750 Å (bottom panel). In each panel we labelled
the identified lines.
the best orbital solution by minimizing the differences between observed and theoretical
points.
From this sample, they extracted all the 5 SB2 systems with the aim of performing an
abundance analysis of both components. Presently they are analyzing HD 191110 using
spectra taken at Catania and extracted from the CFHT archive. To compute atmospheric
parameters of each component, they wrote an IDL procedure to fit simultaneously the
spectra of each star. As an example, the composite Hβ is reported in Fig. 2.27. This
analysis is still in progress.
2.2.3.4
Measurement of magnetic fields in chemically peculiar stars
Since CP stars are characterised by a periodically variable magnetic field, the monitoring
of the Stokes V parameter is a fundamental step to recover the magnetic field topology. Therefore, Leone, Catanzaro and S. Catalano undertook a program to measure the
polarization of the light from CP stars (see, e.g., Leone et al. 2000).
From Hipparcos absolute magnitudes, it is possible to determine the stellar radii and
then, on the hypothesis of a rigid rotator, the inclination of the rotational axes with
respect to the line of sight. On the hypothesis that the magnetic field presents a dominant
dipolar component (that is, where the Stokes Q and U parameters are not necessary to
recover the magnetic configuration), it is possible to determine the angle between the
rotational and dipole axes and the polar strength of the magnetic field. CP stars show
periodic anti-phase light variations short-ward and long-ward of a constant wavelength,
the null wavelength. Leone and collaborators have performed numerical computations
of the expected flux distribution for metal-enhanced atmospheres with different effective
temperature and gravity. From the behaviour of the null wavelength, they confirm the
importance of the non-homogeneous distribution of elements on the stellar surface as the
origin of the light variability. However, to explain the photometric variability of some
stars, they suggested that the flux distribution is also influenced by the contribution of
40
CHAPTER 2. RESEARCH
Figure 2.23: Helium lines observed in the visible spectrum of HD 207538. For each line we
overplotted the corresponding synthetic profile (solid/red curve). The helium abundance
used is log = 11.30.
the magnetic field to the hydrostatic equilibrium.
In order to improve the polarization measurements and extend the sample of observable
stars, Leone, S. Catalano and Catanzaro proposed the development of a spectropolarimetric modulus for the Telescopio Nazionale Galileo, which was subsequently designed
and built in collaboration with the technical staff of Catania Observatory and R. Gratton
and R. Claudi of Padua Observatory.
This work led to the polarimeter of the high-resolution spectrograph (SARG) of Telescopio Nazionale Galileo which has been presented by Leone et al. [114, 115].
2.2.4
Formation and evolution of stars
INAF Researchers:
G. Catanzaro, G. Lanzafame, F. Leone, A. Magazzù,
S. Scuderi
University Researchers: G. Belvedere, R. A. Zappalà
IRA Researcher:
G. Trigilio, G. Umana
PhD Students:
G. Palazzo, R. G. Pizzone
Fellow:
V. Costa
2.2.4.1
Hot stars in Local Group galaxies
Local Group galaxies are commonly considered as important astrophysical laboratories
useful to study the star formation history in environmental conditions different from those
in the Milky Way.
In this framework Catanzaro and Scuderi, in collaboration with L. Bianchi (Johns
Hopkins University, Baltimore, MD, USA) continued their effort aimed at characterizing
41
Figure 2.24: Equivalent width variations of HD 124224 versus phase. Equivalent widths of
the HeIλ4471 Å have been taken from Kuschnig et al. (1999). Magnetic data are plotted
with different symbols according to their source: open circles for those after Borra (1980),
while filled circles for those after Pyper et al. (1998). Photometry is taken from Hipparcos.
the content of two nearby galaxies of the Local Group: M 33 and NGC 6822. They analyzed new spectroscopic data for eight objects (seven stars and the nucleus) in M 33 and
three stars in NGC 6822. The observations have been performed with the ISIS spectrograph mounted on the 4.2-m William Herschel Telescope at the Observatorio del Roque
de los Muchachos (La Palma, Spain).
For all the stars they derived important atmospheric parameters, such as effective
temperature and gravity. For those showing clear evidence of stellar emission in Hα, they
estimated also the mass-loss rate. Examples of their results are reported in Fig. 2.28.
In summary, in M 33 they found 5 hot star candidates out of 7 stars analyzed, and
2 out of 3 in NGC 6822. Although the limited data quality does not afford a precise
measurement of stellar parameters, their results indicate that the observed fields sample
very rich OB associations. Their spectra add new data-points to the census of hot massive
stars in these nearby Local Group galaxies [37].
2.2.4.2
Stellar Populations studies using HST
M. Romaniello, Scuderi, N. Panagia and R. P. Kirshner have developed a new technique
based on multi-band near ultraviolet and optical photometry to measure both the stellar
intrinsic properties, that is luminosity and effective temperature, and the interstellar dust
extinction along the line of sight to hundreds of stars per square arcminute. The yield is
twofold. On the one hand, the resulting reddening map has a very high spatial resolution,
of the order of a few arcseconds, and can be quite effectively used in regions where the
interstellar material is patchy, thus producing considerable differential extinction on small
angular scales. On the other hand, combining the photometric information over a wide
baseline in wavelength provides an accurate determination of temperature and luminosity
42
CHAPTER 2. RESEARCH
Figure 2.25: Equivalent width variations of HD 142990. Photometry is taken from Hipparcos. Magnetic observations after Borra et al. (1983).
for thousands of stars. As a test case, they studied the region around Supernova 1987A
in the Large Magellanic Cloud imaged with the WFPC2 on board the Hubble Space
Telescope. Figure 2.29 shows the H-R diagram of the stars in the region [23]. Furthermore,
they applied this technique to two other fields in the LMC (Romaniello et al., 2003,
submitted to A&A).
2.2.4.3
Star formation in the bulge of M51
H. Lamers and collaborators (including Scuderi) studied the inner kpc of the interacting
galaxy M51 in six bands from 2550 Å to 8140 Å using observations with the WFPC2 on
board the Hubble Space Telescope. The extinction properties, derived in four fields in and
outside dust lanes in the bulge, are similar to the Galactic extinction law. The reddish
stellar population has an intrinsic color of (B − V )0 ' 1.0 suggesting an age in excess of
5 Gyrs. They found 30 bright point-like sources within 110 to 350 pc from the nucleus
whose spectral energy distributions were compared with those predicted for models of
clusters or single stars, supporting the conclusion that the point sources are indeed single
stars [16].
2.2.4.4
Searches for brown dwarfs
Magazzù, together with colleagues at IfA, CFHT, and Grenoble Observatory, has searched
for brown dwarfs in a CFHT survey of the Taurus star-forming-region [117]. In particular,
infrared spectra of brown dwarf candidates, obtained with NICS at Telescopio Nazionale
Galileo, led to the discovery of six new substellar objects [116]. Together with colleagues of
Arcetri and Telescopio Nazionale Galileo, a new classification scheme for infrared spectra
of very cool objects has been presented [90].
43
Figure 2.26: Behavior of equivalent width versus effective temperature for our sample of
CP stars. Points represent the observations, error bars extend by 1σ. Curves represent
the NLTE calculations by Leone & Lanzafame (1998) for three different values of log g:
3.5 (long dash), 4.0 (short dash) and 4.5 (dot).
2.2.4.5
The radio emission of β Lyrae
Umana, Leone and Trigilio presented new observational evidence that supports the presence of an extra source of continuum emission in the binary system β Lyrae. New VLA
and IRAM observations, together with published data from the literature and ISO archive
data, allowed them to build the Spectral Energy Distribution of the binary between 5×109
Hz and 5 × 1015 Hz. The radio-millimeter part of the spectrum is consistent with free-free
emission from a symbiotic-like wind associated with the primary component and ionized
by the radiation field of the hidden companion. Furthermore, they also considered the possibility that the observed radio flux originated from collimated radio structures associated
with the mass-gaining component and its disk (conical thermal jets). An extrapolation of
this emission to the far-IR part of the spectrum indicates that in both cases the free-free
contribution at these frequencies cannot explain the observations and that the observed
infrared excess flux is due principally to the secondary component and its associated disk
[26].
2.2.4.6
Nuclear Astrophysics
A group of researchers of Osservatorio Astrofisico di Catania (OAC), Dipartimento di
Fisica e Astronomia and Dipartimento di Metodologie Chimiche e Fisiche per l’Ingegneria
of the University of Catania, Istituto Nazionale di Fisica Nucleare (INFN) and Laboratori
Nazionali del Sud (LNS) have been maintaining a scientific collaboration on topics concerned with the Nuclear Astrophysics research field, and devoted both to experimental
and theoretical activities.
Some basic problems arise when facing the study of nucleosynthesis processes in stars
or interstellar medium as well as of cosmological nucleosynthesis. Experimental informa-
44
CHAPTER 2. RESEARCH
Figure 2.27: Simultaneous fit of the composite Hβ of HD 191110. The observations have
been carried out at the 91 cm telescope of the Catania Astrophysical Observatory with
R = 14000. With dashed blue and red lines we showed the model adopted for each
component, while solid green line represents the composite synthetic spectra.
Figure 2.28: Normalized spectra of stars observed in M 33. The smooth thick lines are
the models for the adopted temperatures and gravities with an estimated wind emission
(red lines), whereas the dashed (blue) lines refer to the photospheric models calculated
before the mass-loss correction.
45
Figure 2.29: HR diagram for the 13,098 stars detected in the control field for SN1987A. Black
dots are the 4,912 stars with δ log(T e ) < 0.05. The open squares indicate stars for which the
F300W magnitude is ill-determined because of saturation and, hence, the fit was performed
excluding this filter. The theoretical ZAMS is indicated by a solid line.
tion on the cross sections of the many reactions involved in these processes is quite sparse
and difficult to improve. This is due to the low range of energies (∼ 1 − 1000 keV) at
which these reactions typically occur. Because of the “Coulomb barrier” affecting charged
particle induced reactions, cross sections in the 10−9 −10−12 barn range are expected. This
typically allows only a small number of “events” to be detected in laboratories into respect
to the background in direct experiments.
For these reasons, cross sections at energies above those typical of astrophysical environments are usually measured and then extrapolations at lower energies are used. This
procedure gives rise to significant uncertainties.
The development of indirect methods for cross section measurements is complementary
to the approach described above. These are based on the analysis of reactions different
from the one under study, which are both easier to study and useful to extract information
on the properties of interacting nuclei. The Trojan Horse method is one of these (a given
reaction A(x, y)D is studied through measurements made on another reaction A(c, ..)...
in which c is a “cluster” of two particles: x + s, where x is the projectile of the reaction
under study, while s acts as a “spectator” under specific reaction kinematic conditions).
Another experimental obstacle concerns with the many unstable nuclear species involved in nucleosynthesis processes, so that specifically designed facilities to handle radioactive targets and Radioactive Ion Beams (RIB) are required in order to measure reaction cross sections. One of these facilities is currently under development at the Laboratori
Nazionali del Sud (INFN) - Catania (Excyt project: www.lns.infn.it/excyt/index.html).
Together with these experimental difficulties there are also problems more strictly connected with the nucleosynthesis process dynamics: a) the “astrophysical environments”
in which these processes may occur have to be characterized; this requires a connection
between the analysis of observational data (both on the physical conditions of these envi-
46
CHAPTER 2. RESEARCH
ronments and on the abundances of chemical species) and the development of theoretical
models; b) the mechanisms responsible for the synthesis of the various nuclear species in
a given environment have to be found, and this requires numerical simulation codes for
these processes. These codes include a wide range of data on reaction rates, halflives,
nuclear masses, nuclear energy levels, spins of many involved nuclear species. We lack
experimental measurements on a great part of these data, so that many are obtained
through both microscopic and statistical nuclear models.
On the s and p processes. It is known that the binding energy per nucleon of the various
stable nuclear species shows a maximum for species with A ∼ 56, and a “peak” on
the isotopic composition curve for the solar system is present at these nuclear masses.
Moreover, the exo-thermic fusion reaction processes responsible for energy production in
stars are not able to account for the production of isotopic species heavier than 56 Fe.
The processes which are believed to be responsible for the synthesis of heavy isotopes
(A > 56) are typically named with the following letters: s (slow neutron capture), r
(rapid neutron capture) and “p” (responsible for the production of p isotopes).
The isotopic species classified as “p isotopes” are a group of 35 isotopes (from 74 Se
up to 196 Hg) on the proton-rich side of the “stability valley” of the nuclei chart. Their
synthesis cannot be accounted for through the s and r processes. They are believed to
take origin through “photo-erosion” of neutrons, α particles and protons involving isotopes
with A > 75 − 80 and previously formed via the s process. These reactions should occur
on the Ne-O layer of massive stars (stars that can develop core-collapse supernova events,
with masses greater than about 10 solar masses) during their pre-supernova phase or their
explosion as type II supernova.
V. Costa, L. Iapichino and Zappalà examined the physical conditions which are suitable for the development of the p process and investigated also on the impact that the
uncertainties on the s process have on the p process outcome. This study has been performed through reaction network simulation codes including about 400 nuclear species for
the s process and about 2000 for the p process. After having performed a preliminary
study on the physical conditions (temperatures, densities, initial isotopic abundances,
process timescales) that are suitable for the p process, the p processe simulation code has
been applied to supernova explosion temperature and density profiles of the layer of a 25
M star (initial mass at the ZAMS) obtained from a recent evolutionary stellar model.
Moreover, attention has been concentrated on the large uncertainty of the reaction
rate 22 Ne(α, n)25 Mg. The underproduction of the p isotopes 92 Mo, 94 Mo, 94 Ru, 96 Ru is a
traditional problem of the above described model for the p process in massive stars, and
it is mainly due to insufficient production of s nuclei with mass A ∼ 90 − 130 during the
core He-burning s process, at least when the standard value of the rate for the reaction
22
Ne(α, n)25 Mg is used. If higher values of the rate were used (inside the uncertainty range
reported in the literature), it would be possible to partially solve this problem. Therefore,
authors they examined of the role played by the reaction 22 Ne(α, γ)26 Mg, clarify some
aspects of the s process neutron balance [101].
Now a new study of the “weak component” of the s process is being developed through
a new nucleosynthesis code, which includes an algorithm capable of evaluating the truncation error in numerical integrations. This new study is aimed at the analysis of the
uncertainties connected with the stellar model, and particularly to convection treatment,
through the use of a stellar evolution code which can handle convection via two different
47
approachs.
2.2.4.7
Accretion disk models
The formation of accretion disks, with dimensions of the involved structures spanning a
range from ∼ 105 − 106 m (binary systems of compact objects) to ∼ 1021 m (galaxies),
is a frequently observed phenomenon in astrophysics. It is triggered and governed by
two fundamental physics laws: gravitation and angular momentum conservation, which
are responsible for the formation of a plasma disk around central object, while viscosity
and radiative emissions determine the loss of energy and angular momentum of orbitating
matter and the subsequent fall of the “accreted” onto the central object.
It is generally believed that the origin and evolution of many observed astrophysical
phenomena such as novae, some classes of supernovae, X and γ emissions, AGN (Active
Galactic Nuclei) could be linked in some way to the formation of accretion disks. Therefore, the development of fluid dynamic models to understand the basic working features
of these structures could be the key for the understanding of a wide range of astrophysical
phenomena. In many of these structures, nuclear reactions occur, and they can play an
important role both for energy generation and for chemical evolution.
Spiral structures and shocks often appear in astrophysical gas dynamics, particularly
in accretion-disc simulations, but they are difficult to follow numerically. Belvedere and
G. Lanzafame considered a black hole of M1 = 8 M as a primary and a small secondary
of M2 = 0.5 M , following the idea that a low M2 /M1 ratio would favour spiral structure
and possibly spiral shock onset through gas compression induced by a strong gravitational
attraction. In the framework of Smoothed Particle Hydrodynamics (SPH), they performed
two 2D models and two 3D models. Simulations in either pair are distinguished by the
adopted gamma value (low and high compressibility cases). Indeed, both 2D models
reveal the existence of spiral structures in the disc bulk. Furthermore, spiral shocks at
the outer disc edge are evident for the high-compressibility 2D model. Spiral structures
appear to develop also for the 3D high-compressibility model. Instead, for the 3D lowcompressibility model, no clear conclusion can be drawn as the number of particles (and
thus the SPH resolution) is too low [3].
G. Lanzafame, V. Costa, Zappalà and Belvedere investigated the inclusion of chemical
evolution in SPH models of accrection disks. The SPH technique has been developed to
study “single-component” fluids and it needs specific changes to handle phenomena like
diffusion, mixing, chemical or nuclear reactions, which are typical of multi-component
fluids. After a preliminary study on the role of viscosity [113], a study on the technique
to be used in order to insert diffusion processes in the SPH code has been carried out, as
a basis for the subsequent future insertion of a “5-10 species” reaction network [73].
2.2.4.8
Determination of the physical parameters of close binaries
Frasca, S. Catalano, Marilli and collaborators obtained for RT Lacertae, a magnetically
active close binary, high quality radial velocity measurements which allowed them to
determine accurate values of its orbital parameters. A steady decrease of the barycentric
velocity from 1920 to 2000 has been pointed out and has been discussed in the context of
a third body hypothesis [15] (Fig. 2.30).
Orbital parameters and radial velocities of the single-lined active binary FG UMa have
48
CHAPTER 2. RESEARCH
Figure 2.30: The systemic RV of RT Lacertae in four observing seasons is displayed
by filled dots. The orbital solution derived by İbanoǧlu et al. (2001) is shown with a
continuous line. The dotted line represents a solution with a larger period and mass of
the third body, which fits better the observations.
been derived from medium resolution spectra obtained with the REOSC spectrograph at
91-cm telescope [137].
Messina, Frasca and S. Catalano continue a photometric and spectroscopic study in
collaboration with Isik from Akdeniz University on the chromospherically active triple
system DH Leonis [110].
2.2.5
Search for extra-solar planets
INAF Researchers:
G. Bonanno, R. Cosentino, A. F. Lanza, I. Pagano, S. Scuderi
University Researchers: M. Rodonò
Since 1995, when the Jupiter-like planet 51 Peg b (Mayor & Queloz 1995) was discovered, identification and study of extrasolar planets are between the main goals of the
international astronomical comunity. The final aim will be the discovery of other habitable
planets and/or the confirmation of existence of life on them.
Radial velocity exo-planet search. Since year 2000 the SARG team (i.e., the researchers
and technicians who partecipated to the design and building of the high-resolution spectrograph for the Telescopio Nazionale Galileo, among whom the Catania technological
group, led by G. Bonanno, Cosentino and Scuderi, have been playing a fundamental role)
has undertaken a program to search for planets in binary systems [109]. The first result
obtained by the team was the discovery that the components of the wide binary HD
219542 differ in metallicity of about 0.1 dex (Gratton et al. 2001). After two years of
high-precision radial velocity monitoring of the two components of the binary performed
at Telescopio Nazionale Galileo using the high-resolution spectrograph SARG, they found
no indication for radial velocity variations above the measurements errors (∼ 5 m/s) for
the metal-enriched component. This allows to place limits on the presence of close-in
planets around the star [68]. On the other hand, the radial velocity of HD 219542b shows
low-amplitude variations with a period 112 days (see Fig. 2.31) at a moderate confidence
49
Figure 2.31: The radial velocity of HD 219542b phased to the 112.1 days period of the best
orbital solution.
level. This might suggest the presence of a Saturn-mass planet, although it is still possible
that these variations are due to a moderate activity level of the star (Desidera et al. 2003,
submitted to A&A).
Stellar magnetic activity and exo-planet search. The magnetic activity of solar-like
stars, even at the low level characteristic of our Sun, is a potential source of problems in
the search for exo-planets. As a matter of fact, it affects the radial velocity measurement
accuracy up to a few tens of m s−1 as discussed by, e.g., Saar & Donahue (1997) and
also the relative variation of the flux integrated over the stellar disk up to a few 10 −3 , in
the case of active regions having extensions comparable to those of the Sun. This may
severely limit the efficiency of detection of Earth-sized planets by means of the transit
method, which should be feasible from space by the recently proposed COROT, Kepler
and Eddington missions.
The Catania group working on stellar activity has offered his collaboration to the team
involved in the exo-planet search for the COROT mission in order to improve the transit
detection algorithms. Specifically, Lanza, Rodonò and Pagano, in collaboration with P.
Barge and A. Llebaria from Laboratoire d’Astrophysique de Marseille and other people
working on the exoplanet transit project have begin to develop methods to reduce the
impact of stellar activity on transit detection. Their approach is based on the analysis
of the variability of the Sun as a star, for which we have the only set of measurements
of accuracy comparable to those of the stellar photometric time series expected to be
obtained by the forthcoming space missions. Therefore, the Catania team analysed and
modelled the rotational modulation signal present in the time variation of the Total Solar
50
CHAPTER 2. RESEARCH
Figure 2.32: Upper panel:the TSI variation with superposed the central transit of an Earthlike planet the TSI variation with superposed the central transit of an Earth-like planet
of radius R = 2.3R⊕ and orbital period of 30.0 d around a 1.0 M star. Lower panel:
the same time series after subtracting the best fit model light curve computed with the
approach proposed by Lanza et al. (2003).
Irradiance (TSI) as observed by the active cavity radiometers of the VIRGO esperiment on
board the satellite SoHO. By means of the techniques previously applied to the modelling
of light curve sequences of magnetically active stars, they were able to model the most
important contribution to the solar flux variability, that is that arising from the growth
and decay of the largest active regions whose visibility is modulated by the rotation of the
Sun. After subtracting the best fitting model of their contribution, the residual variability
is reduced by a factor of 20 − 30, which should allow to detect easily the transit of an
Earth-sized planet across the disk of a Sun-like star even during period of maximum
activity, as it is shown in Fig. 2.32. The preliminary results of the application of the light
curve fitting method have been presented in [76], while a full account is in preparation by
Lanza et al. (2003).
2.3. EXTRA-GALACTIC ASTROPHYSICS AND COSMOLOGY
2.3
Extra-galactic Astrophysics and Cosmology
INAF Researchers:
2.3.1
51
V. Antonuccio, U. Becciani, A. Bonanno, S. Catalano, A. Frasca,
A. Magazzú, E. Marilli
Cosmology: Galaxy Formation
The activities in Cosmology and Galaxy Formation are tightly connected to the activities
on Computational Astrophysics. Besides developing N-body codes and visualization and
analysis tools, simulations of the evolution of the Large Scale Structure of the Universe
are performed, with two main aims:
• elucidating the properties of galaxy halos forming in underdense environemnts;
• preparing realistic models of the magnetic field distribution in the Local Group
The latter activity is particularly useful also for the modelling of the propagation of
cosmic rays (and particularly of Ultra High Energy Cosmic Rays).
In aprticular, concerning the first issue, we have used the results of a high resolution
N-body simulation to investigate the rôle of the environment on the formation and evolution of galaxy-sized halos. Starting from a set of constrained initial conditions, we have
produced a final configuration hosting a double cluster in one octant and a large void
extending over two octants of the simulation box. We concentrated our attention on gravitationally bound galaxy-sized halos extracted from the two regions. Exploiting the high
mass resolution of our simulation (mbody = 2.1 × 109 h−1 M ), we focussed on halos with
a relatively small mass: 5 × 1010 ≤ M ≤ 2 × 1012 M . We have studied two statistics:
the relationship between 1-D velocity dispersion σv , and mass M0 , and the probability
distribution of the spin parameter P (λ). We have found a clear difference between halos
lying in overdense regions and in voids. The σv − M , relationship is well described by
the Truncated Isothermal Sphere (TIS) model introduced by Ileev, Shapiro and Raga
(2001), but the slope of the relationship is larger in voids. We have studied in more detail
the TIS model, and we found new relationships between the truncation radius and other
structural parameters. After a comparison with the simulation (see Fig 2.33), we have
concluded that the structural properties of our halos are well described by the TIS model,
although not by the minimum energy solution. We have also shown that the dependence
of the statistical properties on environment can be quantitatively accounted for within
this model by a different dependence of the dimensionless truncation radius on mass in
clustered and void regions.
2.3.2
Cosmology: Universe models
In collaboration, with M. Reuter, Institut fuer Physik, Universitaet Mainz, Germany,
and E. Bentivegna, Catania University, A. Bonanno has continued the study of Universe
models with dynamically evolving Newton constant G and cosmological constant Λ from
the renormalization group equation [6, 5], by studing a cosmological perturbation theory.
E. Bentivegna, A. Bonanno, M. Reuter, using median statistics and a Bayesian model
selection criterion have shown that this new cosmology has even better chances of being
52
CHAPTER 2. RESEARCH
Z (Mpc/h)
20
−−−−−−
−−−−−−
|
10
|
|
|
0
|
|
−10
−20
−20
−10
1
1.5
0
Y (Mpc/h)
10
2
2.5
20
3
Figure 2.33: Galaxy structure simulation: Snapshot at the end of the simulation. The
run was perfomed using more than 16 million particles. The scale of grey corresponds to
density in logarithmic units. The large void is clearly seen in projection extending over
the lower left octant.
the correct theory of the late Universe than any standard cosmology. A. Bonanno has also
been invited to held a series of lectures at the University of Naples, on the renormalization
group and its applications in Physics and Astrophysics. He is collaborating with C.
Rubano and G. Esposito on a new lagrangian and hamiltonian formalism for a modified
theory of gravity.
2.3.3
Extra-galactic astrophysics: U B V photometry of BL Lac
objects, Gamma Ray burts observation
In collaboration with colleagues of “La Sapienza” Rome University and INAF-Torino
Observatory, A. Frasca, E. Marilli and S. Catalano have carried on photometric U B V
observations of BL Lac objects, within international programs of short- and long-term
multi-band monitoring (WEBT). In particular, results of a multi-site optical campaign in
which were collected more than 15 000 observation of BL Lac, from May 2000 to January
2001, have been published [28]. The Catania group has given a significant contribution
2.4. LABORATORY OF EXPERIMENTAL ASTROPHYSICS AND SOLAR SYSTEM PHYSICS53
to the determination of the “intra-day” variation behaviour and of the spectral indices
of energy distribution of the source. From the analysis of colour indices, two different
mechanism have been proposed to explain the long-term variation and the fast flares
phenomena. The first one, essentially achromatic, is mainly based on geometrical effects,
i.e. the variation of the relativistic Doppler factor δ probably due to a change of the
viewing angle, while the second one, responsible for the outburst, is strongly wavelength
dependent. The spectrum become flatter when the source gets brighter. Variability on
time scales as short as 7 hours have been also inferred from autocorrelation analysis [28,
75].
Simultaneous optical and X-ray BeppoSax observations of the two BL Lac objects
OJ 287 and MS 1458+22 have been performed in 2001 [44]. These observations have
allowed the authors to study the spectral energy distribution (SED), which is different
for the two blazars, but can be well reproduced by log-parabolic spectral laws. This
law, already observed for the synchrotron emission components in other blazars, can be
explained if the emitting particles are accelerated by some statistical mechanism having
a probability of energy gain that is a decreasing function of the energy itself.
A. Magazzù has taken part in international observational campaigns aimed at the
detection and study of Gamma Ray bursts afterglows, using the Telescopio Nazionale
Galileo [45].
2.4
Laboratory of experimental astrophysics and Solar System physics
INAF Researchers:
PhD Students:
Fellowship:
Students:
Technical staff:
2.4.1
G.A. Baratta, G. Leto, M.E. Palumbo, G. Strazzulla
M. Domingo, O. Gomis
G. Ferini
E. Di Stefano
F. Spinella, G. Carbonaro
Background
Solid materials in space, namely ices, silicates and carbons, are present in different environments such as the interstellar medium, comets, asteroids and outer solar system
objects. As it is the case for the majority of astrophysical objects, all of the information
astronomers have on the physico-chemical properties of solid materials in the universe
is obtained by analyzing electromagnetic radiation emitted, absorbed, or reflected from
solid objects.
Refractory dust particles (average radius ∼0.05 mm) made of silicates or carbonaceous
material are released from stars (mainly in the red giant phase) in whose atmospheres
they are formed, into the interstellar medium (ISM). Occasionally diffuse clouds in the
ISM (nH ∼1-103 cm−3 , T∼100 K; where nH is the total number of H atoms, i.e. H+2H2 ,
H2 being the numeric density of the hydrogen molecules) contract to form dense molecular
clouds (nH ≥104 cm−3 , T∼10-20 K). In these regions the numeric density of dust particles
(grains) is nd ∼ 10−12 nH . The temperature of the dust in dense clouds is as low as
10-20 K and thus virtually all atoms and molecules (with few exceptions such as He
and Ne) that impinge on the grains stick on the surface to form ice mantles with an
54
CHAPTER 2. RESEARCH
average radius estimated to be of the order of 0.1 µm. As the cloud contracts, atomic
hydrogen is converted into molecular hydrogen, through H+H combination on grains and
the consequent release of H2 in the gas phase. This process has important consequences
on the chemistry of icy mantles: when H dominates, hydrides species such as H2 O, CH4 ,
NH3 , CH3 OH are expected to form leading to a mantle dominated by polar molecules.
When H2 dominates, molecules such as the observed CO and the inferred O2 and N2
accrete on grains to form an outer shell of apolar ices. When a star is observed from
behind a dense molecular cloud (field star), its light is absorbed by the matter in the
cloud and the analysis of the observed spectrum gives information on the composition of
the cloud. While the electromagnetic radiation in the UV-Vis spectral range is completely
absorbed, in dense molecular clouds, it is possible to observe in the IR the vibrational
absorption spectrum due to the presence of refractories and ices along the line of sight.
Dense molecular clouds, after further contraction, are the places where stars are born.
The observation of protostars, (stars still embedded in their placental cloud), is a further
probe of the presence of ices in the clouds. In this case the almost blackbody continuum emitted from the young object is absorbed by grains whose temperature changes
as a function of the distance from the object. These observations, mainly obtained by
IR spectroscopy, may reveal the evolution of ices due to thermal and/or energetic (e.g.
interaction with UV photons and/or stellar particle winds and cosmic rays) processing.
Ices are also present on many objects in the Solar System such as the satellites of the
external planets (Jupiter and beyond), the planet Pluto, the so called trans-Neptunian
objects (a class of numerous small objects not yet well investigated), and comets. In this
case, too, the study of the composition of the ices is based on the study of the electromagnetic radiation coming from the Sun and reflected by the surface to the observer.
Energetic (keV-MeV) particles and UV photons impinging on solid surfaces made of
refractory (carbonaceous and/or silicates) materials and/or ices are present in a variety
of environments in space including the interstellar medium and planetary systems. The
study of the effects of ion irradiation and UV photolysis has been based on laboratory
simulations of relevant targets bombarded with fast, charged, particles and by Lyman-α
photons under physical conditions as similar as possible to the astrophysical ones. Two
main effects occur: (1) some material is eroded from the target (sputtering) and (2) some
physico-chemical modifications are induced, including the formation of different molecules.
Fast ions penetrating solids deposit energy in the target by elastic interactions with
target nuclei and by inelastic collisions causing ionizations and excitations. Thus chemical
bonds are broken along the path of the incoming ion and physico-chemical modifications
occur, including the formation of molecules originally not present in the target. These
molecules include species that can be both more volatile than the parent ones and less
volatile. When carbon is an important constituent of the irradiated target it gives rise to a
refractory residue which is left over after warming up to room temperature. That residue
has a complex structure, and after prolonged irradiation evolves to form hydrogenated
amorphous carbon. In the case of UV photolysis, the energy is released to the target
material through single photo-dissociations, photo-excitations or ionization events per
incoming photon. Also in this case new molecular species are formed.
Different techniques have been used, by different groups, to characterize the chemistry
induced by energetic ions and UV photons. In our laboratory we have been using, for
about 20 years, in situ IR and Raman spectroscopy.
A number of different ices and mixtures have been irradiated to study their chemical
2.4. LAB. OF EXPERIMENTAL ASTROPHYSICS & SOLAR SISTEM PHYSICS
55
and/or structural evolution. Usually samples are prepared at low temperature (10-20
K) and their spectral characteristic recorded before, during and after processing with
energetic ions (3-60 keV) and UV photons (Lyman-α, 121.6 nm=10.2 eV). Targets are
subsequently warmed-up and spectra are taken at increasing temperatures (20-300 K).
This research, in the past 20 years, has been financially supported by ASI, CNR,
Assemblea Regionale Siciliana, CNAA, and MIUR. In year 2002, a research proposal,
coordinated by G. Strazzulla and involving also the experimental groups of Napoli (OACapodimonte) and Lecce (University) has been submitted and approved by MIUR-Cofin.
This proposal titled “Laboratory studies of silicates present in the Solar System” is summarized in the section on “Future studies” with a closer look to the role of Catania-Lasp
group.
2.4.2
Experimental facilities
2.4.2.1
The Vacuum Chamber
The in situ analyses are performed in a stainless steel high vacuum chamber (see inset in
Figure 2.34). Inside the chamber, in which pressure is kept below 10−7 mbar, a substrate
(crystalline silicon) is placed in thermal contact with a cold finger whose temperature can
be varied between 10 K and 300 K. A needle valve is used to admit pre-prepared gases
(or mixtures) into the chamber, where they freeze on the substrate. A He-Ne laser can be
used to monitor the thickness of the ice film during accretion; this is achieved by looking
at the interference pattern (intensity versus time) given by the laser beam reflected at
an angle of 45o both by the vacuum-film and film-substrate interfaces. Solid samples are
simply mounted in thermal contact with the cold finger.
2.4.2.2
The Ion Implanter
The vacuum chamber is interfaced with an ion implanter (30 kV; Danfysik) from which
ions with energy up to 30 keV (60 keV for double ionizations) can be obtained. The
ion beam produces a 2×2 cm2 spot on the target and current density in the range of
100 nA cm−2 to a few µA cm−2 . The amount of energy released to the icy samples
(dose) is expressed in units of eV/16 amu and is calculated from the knowledge of the
ion fluence (ions/cm2 ), the stopping power (eV cm2 /molecules) of the chosen projectile,
and its penetration depth or range in the target (molecules cm−2 ). The first is given
by a current integrator on the path of the ion beam, which measures the charge which
reaches the sample during irradiation; the other two parameters are well known and can
be provided by software such as SRIM. The penetration depth of 30 keV He+ ions in
the icy mixtures studied is about 0.3 µm. In order to have thicker irradiated samples,
and thus spectra with a better signal-to-noise ratio, we irradiate the icy mixtures during
deposition. In this case the dose is estimated from the knowledge of the deposition rate
(molecules cm−2 s−1 previously calibrated), the ion flux (ions/cm2 sec) and the energy of
impinging ions (eV). When irradiated samples are thicker than the penetration depth of
impinging ions, the doses are given in units of ions/cm2 . A schematic depiction of three
different types of performed experiments is reported in Figure 2.35.
56
CHAPTER 2. RESEARCH
Ion Implanter (30 kV)
Multiline Ar ion laser
Triple SPEC monochromator
and red–enhanced phototube
1.9 m
Confocal illuminator
Ion source
and accelerator
Ingoing laser beam
Collected
Raman
beam
Objective
Stainless steel
vacuum chamber detail
KBr
windows
Ion beam / He–Ne laser
Silicon
substrate
(10–300 K)
KBr window
2.5 m
Magnet
(ion selector)
He–Ne
laser
Ion beam / He–Ne laser
Figure 2.34: Schematic view of the experimental apparatus used for in situ Raman spectroscopy of ion irradiated samples. The inset gives details of the vacuum chamber. In
order to obtain infrared spectra the glass objective is removed. A hole in the sample
holder allows the infrared beam to transmit through the substrate and the sample.
2.4.2.3
Upgrade of the ion implanter
The final part of the year has been dedicated to the upgrading of the ion implanter. A
post-acceleration has been settled in order to have ion beams up to 200 keV in case of
single ionization and 400 keV for double ionized ions. The new beam line has two main
advantages. First of all the penetration depth (that is the range which ions travel in
matter before being stopped) for a given material depends on the energy of impinging
ions. Thus it will be possible to irradiate thicker samples. This in turn means that it
will be possible to obtain spectra with higher signal to noise ratio and to detect weaker
features in the spectra.
The total energy which ions release in the target per unit path length (also referred
to as stopping power) is given by the sum of the elastic and anelastic stopping powers.
The relative amount of these contributions depends on the mass and energy of impinging
ions. Thus the new beam will give us the possibility to span a larger range of different
stopping power values allowing us to study those effects which depends on the specific
interaction (elastic versus anelastic) of ions with matter. A view of the setup of the
upgraded implanter is shown in Figure 2.36.
2.4.2.4
The UV lamp
A hydrogen microwave discharge resonance lamp (Opthos Instruments) is interfaced with
the vacuum chamber through an MgF2 window; from this lamp mainly 10.2 eV (λ=121.6
nm) photons are obtained. An aluminium light collector is placed at the end of the lamp
57
ION IRRADIATION EXPERIMENTS
Target (0.2-0.8 µm)
Target (1-6 µm)
Target (1-10 µm)
Ions (30-60 keV)
Ions pass through the target
Irradiation during deposition
Implantation
Figure 2.35: Schematic description (not to scale) of three different types of experiments
performed. The sketch on the left hand side refers to ion irradiation of icy films thinner
than the penetration depth of impinging ions. In this case ions pass through the sample.
The middle sketch refers to an icy sample irradiated during deposition. The process stops
when the sample is as thick as required. The sketch on the right hand side refers to ion
irradiation of a sample much thicker than the penetration depth of impinging ions. In
this case, only the uppermost layers of the sample are irradiated. The ice underneath
remains unprocessed and ions remain implanted in the sample.
in order to increase the number of UV photons that reaches the sample. A light detector,
placed at the end of the aluminium light collector, is used to measure the UV flux during
photolysis. The detector is a platinum wire which gives a current, by the photoelectric
effect, proportional to the UV flux. The wire detector has been calibrated using the
procedure described in Baratta et al. 2002.
2.4.2.5
Infrared Spectroscopy
Infrared spectra are obtained by a Fourier Transform Infrared (FTIR) spectrometer
(Bruker Equinox 55). The sample holder has a hole, with a diameter of 4.5 mm, which
allows the infrared beam to transmit through the substrate and the sample. The infrared
beam forms an angle of 45o with both the ion beam and the substrate holder. Thus, spectra can be taken in-situ before, during, and after irradiation, without tilting the sample.
Spectra shown in the following are ratioed to the background spectrum, which includes
the substrate, and are taken with a resolution of 1 cm−1 unless otherwise specified.
2.4.2.6
Raman Spectroscopy
Figure 2.34 schematically shows the arrangement used to acquire Raman spectra. A
continuous multiline Ar-ion laser beam (λ=514 nm) enters a confocal illuminator per-
58
CHAPTER 2. RESEARCH
Figure 2.36: The new setup of the ion implanter of the Experimental Astrophysics Laboratory at Catania Astrophysical Observatory. After the upgrade from 30 kVolts to 200
kVolts the ion implanter is shielded with a conductive wall. All instruments and control
systems are placed out of the restricted area where the beam is accelerated.
pendicularly to its optical axis, into which it is deflected by a microprism. The confocal
optical system is arranged in such a way that any parallel beam incident along the optical
axis in the opposite direction of the laser is focused onto the entrance slit of the spectrometer (Triplemate SPEX). By means of two flat mirrors, the laser beam is reflected
towards the vacuum chamber, where it is focused on a 40 µm spot on the sample. The
same objective which focuses the laser beam on the sample collects the Raman-scattered
light, which reaches the confocal illuminator going back along the same path of the laser
beam. This confocal system makes it possible to obtain Raman spectra of samples located several meters away from the spectrometer with negligible performance losses. The
substrate holder is mounted at an angle of 45o both with the ion beam and the Ar-ion
laser beam. This configuration offers the advantage that spectra can be easily taken in
situ, even during irradiation with ions, without tilting the sample.
2.4.3
Results
The main results obtained during this year are here summarized.
2.4.3.1
59
Comparison of ion irradiation and UV photolysis of ices
The effects induced by fast ions and UV photons on astrophysical relevant ices have been
separately studied in different laboratory for several years. It is well known that both
processes induce chemical and structural modifications of the ice sample. However only
few laboratories have the capability to study both effects with the same experimental
set-up. Baratta et al. have continued their study on the comparison of the effects induced by energetic ions and UV photons on simple ices namely methane (CH4 ), methanol
(CH3 OH) and water (H2 O) [2, 44]. After ion irradiation and UV photolysis of methane
and methanol the intensity of the original spectral features decreases and new features
appear indicating the formation of other molecular species such as C2 H6 and C3 H8 in
the case of methane, CO and CO2 for methanol. They have found that these effects are
comparable on fresh ices (i.e., after a low dose of few eV released by incoming ions per
molecule of the target) while are different at high dose. Due to irradiation in both cases
the optical constants of the sample change. It is well known that under ion irradiation hydrocarbons evolve towards a polymer-like material and eventually to a refractory residue.
The experiments of UV photolysis also show that a refractory residue is eventually formed.
However while the energy released by ions is independent of the optical constants of the
sample, the refractory residue is opaque to UV photons. Thus at higher doses impinging
ions continue to release energy to the sample which is further modified while UV photons are strongly absorbed at increasing smaller depths as photolysis proceeds and cause
negligible additional modifications. This conclusions are also supported by a combined
processing experiment. An icy sample of pure CH4 has been first processed with UV
photons (up to 35 eV/16amu) and then with 30 keV He+ ions (from 37 eV/16amu to 89
eV/16amu). Results indicate that if a sample previously photolysed is ion irradiated a
steep decrease (at the beginning even steeper than the case of ion irradiation alone) of
CH4 column density is observed [2].
As concerns the effects of ion irradiation and UV photolysis on water ice, Leto and
Baratta [44] performed an experimental study on the structural effects induced by Lymanα photons in crystalline water ice carried out by in situ infrared spectroscopy. They found
that, as already observed in the case of processing with energetic ions, Lyman-α photons
are able to fully amorphize the crystalline water ice structure after a dose of few eV per
molecule.
2.4.3.2
Ion irradiation of frozen hydrocarbons
The discovery of abundant acetylene (C2 H2 ) and ethane (C2 H6 ), along with methane
(CH4 ) as gas phase species evaporated from the cold nucleus of comet C/1996 Hyakutake, and later towards other comets, raised the interest of astrophysicists towards these
species. Furthermore it has been suggested that acetylene and ethane could be present
as condesates in Titan’s stratosphere and perhaps mixed with abundant frozen nitrogen
on Triton and Pluto. Strazzulla et al. and Baratta et al. [25, 32] have irradiated frozen
C2 H2 , C2 H4 , and C2 H6 with 30 keV He+ ions at 12 K to investigate the formation of new
molecules and the development of a refractory residue. Jovian and Saturnian moons are
also bombarded by heavy ions accelerated in the magnetosphere of the planets. Laboratory experiments have shown that when reactive ions (such as H, C, N, O) impinge on
frozen samples, new molecular species which include the projectile can be formed. Thick
samples (that is thicker than the penetration depth of impinging ions) of acetylene, ethy-
60
CHAPTER 2. RESEARCH
2
column density (molecules/cm )
CH4
17
10
+
30 keV He
10.2 eV photons
photons + ions
16
10
0
20
40
60
80
100
120
dose (eV/16amu)
Figure 2.37: Column density of CH4 deduced from 1300 cm−1 band (deformation mode)
after ion irradiation with 30 keV He+ ions (solid circles) and photolisys with Lymanα photons (10.2 eV; open circles). Triangles refers to a sample which has been first
proscessed with UV photons (up to 35 eV/ amu) and then with He+ ions. Straight lines
have been drawn to guide the eye.
lene and ethane have been irradiated with 15 keV N+ ions. In all cases, among others,
new spectral features appear due to N-bearing molecules. This result gives confidence
that nitrogen implantation gives rise to CN bonds in all the studied hydrocarbons and
enforce the possibility of their detection on the surface of Jovian and Saturnian moons.
Recent observations have shown that the surfaces of some objects in the outer solar system, namely Pluto, Triton, and possibly a number of small trans-Neptunian objects, are
dominated by frozen nitrogen mixed with small amounts of methane, carbon monoxide
and dioxide, and water. Many other, even more complex, molecules could be present as
well, although not yet firmly identified. Even if molecular nitrogen is the most abundant
species on the surface of Pluto, the presence of regions rich of methane has been suggested.
On the other hand the spectrum of Triton is compatible with the presence of regions with
water and carbon dioxide spatially segregated. Furthermore, due to planetary climatic
cycles, volatile species sublimate and recondense in a complex manner. Previous laboratory work has concentrated on the study of the effects of ion irradiation of pure CH4 , and
N2 rich mixtures with H2 O and CH4 as minor components. Strazzulla et al. and Baratta
et al. [25, 32] have considered mixtures where water, methane and nitrogen are in comparable amount and that could be relevant to “simulate” those superficial patches where
segregation is taking place. Laboratory experiments have shown that several molecules
containing cyano groups are formed after ion irradiation at low temperature. This findings
is of primary relevance because of their role in the development of a very complex chemistry. These molecules could have been delivered by comets on the primitive Earth during
the early heavy bombardment. Here, they could have contributed to the development of
more complex biogenetic compounds.
2.4.3.3
61
C60 Fullerene
Recently it has been proposed that C60 fullerene may exist in the interstellar medium
although its total amount should be low also because its instability towards the action
of electromagnetic radiation which can cause its dimerization and oligomerization. Additionally, fullerene in space is exposed to the action of energetic ions. To simulate in
the laboratory the effects of ion bombardment Cataldo et al. [10] have bombarded C60
fullerene films with 30 keV He+ ions at room temperature in vacuum. The structural
changes undergone by C60 have been followed by both infrared and Raman spectroscopy.
This latter was the most useful tool for this scope. It has been clearly discovered that at
low radiation dose C60 forms oligomers but at higher doses it is converted into an amorphous carbonaceous matter. Therefore, C60 in space, if condensed on the surface of solid
grains and exposed to any kind of radiation, cannot survive as such but it is converted to
an oligomeric or polymeric form.
2.4.3.4
Nitrogen condensation on water ice
Most of the studies relative to water diluted in different solid matrices have been performed
in the mid-infrared spectral range where fundamental vibrational modes are present.
Palumbo and Strazzulla, [47] have perfomed a new experimental study meant to investigate the spectral characterisitcs in the near-infrared of N2 :H2 O icy mixtures and samples
of N2 diffused in water ice. This spectral range typical of combination and overtone modes,
is relevant to study objects in the Solar System. As a matter of fact, based on observations
in the 0.5-2.5 µm (20,000-4,000 cm−1 ) spectral range, the surfaces of the planet Pluto, of
the major Neptune’s satellite Triton, and possibly of a number of small trans-Neptunian
objects, seem to be dominated by frozen nitrogen mixed with small amount of methane,
carbon monoxide and dioxide, and water. Due to climatic cycles volatile species, such as
N2 , are expected to sublimate and recondense on the surface while less volatile species,
such as H2 O, remain segregated on the surface. Although water easily segregates because
its vapor pressure is so different from that of the dominant nitrogen, it cannot be excluded
that a small quantity of water molecules can be trapped in nitrogen ice. This could be
the result both of a recondensation process of nitrogen from the atmosphere on a waterrich surface patch and of the condensation of the dominant nitrogen along with a small
amount of water vapor, not yet detected, but likely present, in the tenuous atmosphere of
Pluto and Triton. Laboratory experiments have shown that when water is highly diluted
in nitrogen a feature at about 5300 cm−1 (1.88 µm) appears. Palumbo and Strazzulla,
[47] suggest that this band should be searched for on these objects.
2.4.3.5
Asteroids photometry
The data collected during many observational campaigns, made at M.G.Fracastoro station
of Catania Astrophysical Observatory, have been analyzed to derive aspect and position
of asteroids. The axes ratio values and the pole coordinates of 48 asteroids have been
published. For these objects almost three light curves, well distributed in longitude over
time including many oppositions, were obtained. The value of the rotational period for
more than 50 asteroids was also determined and for as many asteroids the known value
was corrected or improved [34]. The V light curves and the B-V mean color index of these
objects are in press [33]. It was scheduled an observational campaign, devoted to Trojans,
62
CHAPTER 2. RESEARCH
NEOs and small size asteroids, that will be made by using the CCD Kodak camera
(see 2.5.4.1) attached to the primary focus of the 67/92 Schmidt of Asiago Observatory.
2.4.3.6
Future studies
“Laboratory studies of silicates present in the Solar System”. The study of the formation
and evolution of different classes of solid bodies in our Solar System is one of the most
relevant and puzzling subjects of modern planetology. A whole research community is
involved, at international level, to tackle a wide variety of open problems concerning the
past and present composition of large and small objects. It is quite evident that such
a broad area of research (and the so many open questions) requires a combined effort
based on laboratory studies, observations and theoretical work, as usually it occurs in
many branches of science. Silicates, carbons and ices are the main components the solid
objects in the Solar System are made of. The Italian groups at Catania, Lecce, and
Napoli have been involved, for several years, in a wide variety of laboratory experiments
aimed at “simulating” materials and/or processes occurring in space and appropriate
to gain information on material properties in a wide set of space environments. The
simulations have been focused on the formation of refractory sub-micrometer silicate and
carbonaceous dust in the atmosphere of evolved stars; their evolution in the interstellar
medium, including amorphous-crystalline transitions and the formation of ice mantles on
the refractory cores, under the effects of external agents (UV photons, energetic particles,
thermal processing, etc.); their evolution around young forming stars; their properties
and endogenous and/or exogenous processing in the very broad set of different objects in
the Solar System.
Along two years Catania-Lasp researchers plan to achieve some specific goals relevant
to the most important open questions. The general aim of the research is to contribute to
a better knowledge of properties of selected silicates of interest to planetology and some
of the physical-chemical processes that might have driven their formation/evolution.
In particular the activity will focus on the study of the following selected silicates:
• Nesosilicates, namely different kinds of olivines (Fe,Mg)2 SiO4 , with different Mg/Fe
ratio, from forsterite (Mg2 SiO4 ) to fayalite (Fe2 SiO4 );
• Inosilicates, namely pyroxenes (Fe,Mg)SiO3 ;
• Tectosilicates, e.g., albite NaAlSi3 O8 , nepheline (Na, K)AlSiO4 and sodalite
(Na,Cl)Al SiO4 .
The detailed study of these materials, along the lines described below, will be possible
thanks to the long lasting experience of the proposing team in the field of laboratory
characterisation of materials of astrophysical relevance and to the wide variety of experimental techniques, instrumentation and tools already available in the groups. The
main available analytical techniques that will be used in the study include: UV-Vis-IR
reflectance, UV-Vis-IR extinction spectroscopy, Raman and micro-Raman spectroscopy,
IR emission spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. The silicates will be studied both as bulk materials and as particulate in selected size
ranges. They will be produced by grinding and sedimentation techniques and by laser ablation under different environmental conditions. After production and characterisation,
63
the samples will be subjected to different processing: annealing, UV and/or energetic
particle irradiation at different temperatures, implantation with reactive energetic ions
(H, C, N, O, Na), hydration. All the analyses will be repeated after the processing to
study the induced effects. UV-Vis-IR diffuse reflectance and Raman spectroscopy will be
performed also “in situ” during irradiation.
The main role that Catania-Lasp group will play in this research is the study of the
spectral properties of the chosen silicates during and after processing with UV photons
and energetic ions. UV irradiation and ion bombardment will be performed to investigate
“in situ”, at low pressure and at different temperatures, some key aspects:
• amorphysation induced on crystalline silicates and changes in the chemical composition (stoichiometric ratios). The techniques used “in situ” will be IR transmission
spectroscopy (IR band shapes are sensitive to the structure of silicates) and, possibly, Raman spectroscopy;
• thermal annealing of silicates amorphised by ion irradiation to compare their crystallisation temperatures with those of amorphous synthesised samples;
• crystallisation of amorphous silicates: is it possible to find a combination of sample
temperature, mass of incident ion and ion beam dose rate (energy deposited per
time unit) sufficient to crystallise the samples? Are those dose rates realistic in
astrophysical environments?
• UV and ion irradiation of albite and nepheline: study of the species released in the
gas phase and changes in the chemical composition of the irradiated surfaces;
• implantation of reactive ions (H, C, N, O, Na) in silicates: do new chemical species
that include the projectile form? It has been already shown, by a study on the
development of -SiH stretching band by proton (1.5 keV) implantation on silicon,
quartz, palagonite and feldspar that the selected samples, but pure silicon, do not
exhibit any clear evidence of the presence of the -SiH stretching band. On the
contrary, some experimental results on the implantation of 30-40 keV C ions into
SiO2 grains or thin films lead to the synthesis of CO and CO2 by bonds formed
between the projectiles (C-ions) and the lattice O atoms;
• all the samples, after irradiation will be extracted and leached in de-ionised water at
100deg C for times between a few hours and a few days to study aqueous alteration;
• during the irradiation experiments we will perform “in situ” diffuse reflectance spectroscopy in the 0.6-3 µm range to study, in particular, the spectral slope to be
compared with those observed in astronomical objects;
• some silicate samples will be coated with layers of organic matter (e.g. produced
by depositing frozen hydrocarbons and irradiating them) and irradiated to study by
diffuse reflectance spectroscopy in the 0.6-3 µm range the variation in the spectral
slope;
• some silicate samples will be coated with layers of water ice and irradiated to investigate the possibility of hydration via intermixing and back-diffusion of water
fragments e.g. H, OH, O.
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CHAPTER 2. RESEARCH
2.5
Catania Observatory Laboratory for Detectors
(COLD)
INAF Researchers:
Students:
Technical Staff:
G. Bonanno, R. Cosentino, S. Scuderi
D. Gandolfi
M. Belluso, P. Bruno, A. Calı̀, M.C. Timpanaro
The main activity of this research group consists in the study and realization of image acquisition systems based on two-dimension detectors and optical instrumentation
for astronomical applications. Typical products of this activity are ”Front-End electronics” for CCD detectors, photon counting systems, acquisition, analysis and reduction of
images, electro-optical characterization of detectors for ground and space telescopes. The
optimization of the CCD controller is centered both on the use of new technology circuits such as DSP and FPGA and on the attenuation of the readout noise to obtain high
signal-to-noise ratios, thus allowing the detection of weak ”features”, e. g. smaller than
1% of the continuum, in the case of spectrophotometry.
Since 1998 the group has begun a search program dedicated to select new detectors useful for astronomical observations, both from Earth and space. In addition to CCDs three
detectors in particular are under investigation: one based on diamond (Cofin. MURST,
ASI), one based on MCP coupled to CMOS-APS sensors to obtain photon counting with
the highest dynamical count rate (CNAA funding), and one based on avalanche photodiodes (SPAD) .
The main facilities and instruments available to the group include:
• a characterization system in the 130-1100 nm spectral range
• two optical benches with several optical components
• a 20” integrating sphere for uniformity measurements of very large detectors as CCD
mosaics
• cryogenic systems with Liquid Nitrogen cooling and thermoelectric cells (Peltier)
and chillers
• a class 100 clean room (12 squared meters)
• various electronic benches equipped with oscilloscopes and several multi-meters
• a software development kit (Xilinx) for programming of electronic FPGA
The group activities in 2002 have been developed in the following areas:
- CCD controller update
- New technology detectors
- Collaboration with industries
- Support for CCD camera and control systems
- Partecipation to international projects
2.5. CATANIA OBSERVATORY LABORATORY FOR DETECTORS (COLD)
2.5.1
CCD controller update
2.5.1.1
CCD controller for TNG
65
The new generation CCD controller, developed by the Italian Detector Working Group
(DWG), is an improvement of the CCD controller in use at TNG. A new interface with
the host computer, based on a high-speed link and PCI board, able to sustain high data
transfer rate has been designed and built (Cosentino et al. 2003a, Proceedings of workshop on ”Scientific detectors for astronomy”, Waimea, Hawaii, in press). The sequencer
has been modified in order to improve high-speed clocks and different reading modes. A
new analogue board based on a fast ADC’s and new signal processing has been designed.
The board is able to process four channels simultaneously allowing high acquisition rates.
The new host interface is a PCI based board, equipped with a full-duplex optical link,
working at 1.2 GBauds. It allows data and telemetry communication (remote to local)
and commands and clocks sending (local to remote). Communication with high-level
languages is guaranteed by low level drivers (Windows NT, 2000 and XP) and a DLL.
Thanks to the high speed link the phases are generated in the host computer and are
rebuilt by the sequencer. All the TTL control signals are generated on the PCI board
(far from the CCD head), while the analogue circuits are next to the CCD head. This
guarantees a high performance in terms of noise immunity.
In summary, the analogue board allows: four selectable input gains and four selectable
bandwidths to work at different readout speeds, the possibility to program the offsets
before and after the CDS stage, to adapt the signal to the A/D converter and the choice
of different references for the dummy input. The bias generator allows 16 programmable
bias voltages with different ranges, divided in four groups. The voltage ranges are: from
15 to 30, from 5 to 15, from -5 to 5 and from -10 to 10 Volts.
2.5.2
New technology detectors
2.5.2.1
CVD Diamonds detectors
The use of polycrystalline CVD diamond for the detection of ionising radiation (including
UV and X-ray) has been widely reported (see for example Pace, Scuderi & Di Benedetto
2000, Diamond and Related Materials, 9, 987). These results highlight the advantages of
diamond as a radiation-hard material with exceptional thermo-mechanical properties. The
importance of material quality in device performance has also been reported. Because of
advances in CVD synthesis technology the electronic properties that are currently achieved
in polycrystalline CVD diamond rival some of the best results obtained with single crystal
natural diamonds. It is important therefore to attempt to characterize the quality of the
material in addition to device performances.
The project has received fundings by MURST in 1998 and by ASI in 1999 and 2001 and is
carried out in collaboration with the Dipartimento di Astronomia e Scienza dello Spazio
of the University of Florence, the Dipartimento di Meccanica e Materiali of the University
of Reggio Calabria and the Dipartimento di Scienze e Tecnologie Fisiche ed Energetiche
of the University of Rome (Tor Vergata).
In the past year the team has worked to the development and the characterization of
large area (1 cm2 ) Vacuum-UV (VUV) CVD diamond photodetectors to address the
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CHAPTER 2. RESEARCH
Figure 2.38: Absolute Quantum Efficiency of a large area CVD diamond device for two different
values of the bias voltage
requirements of space missions where pixel and 2-D arrays are used. The quality of the
CVD diamond was characterized by photoluminescence and Raman spectroscopy. The
performance of these devices in the dark and under illumination was investigated and the
results compared to those from small area detectors based on similar material. Planar
and transverse electrode configurations were used in order to evaluate the possibility of
producing imaging detectors. The spectral analysis of the photocurrent was measured
as a function of several functional parameters and experimental conditions. Figure 2.38
shows the measured quantum efficiency for one of such devices.
2.5.2.2
Intensified Active Pixel Sensor (IAPS)
The activity of development of a new photon counting detector for the astrophysical
applications based on a Micro Channel Plate and a CMOS APS sensor (see Figure 2.39)
has been going on since 2000 on CNAA funds. During 2002 we have realized a new
electronic board with an FPGA XILINX XCV800 which has allowed us to reach a frame
rate of 400 Frame/sec [95, 125]. The software for the control electronics card written in
C++ language and a series of routines writings in IDL language, allow to the user to
measure the characteristics of the system in real time. Furthermore, we have investigated
the possibility to improve the performances of the system trying to reach the maximum
frame rate possible for the APS sensor, that is 500 frames/s, and also to increase the
compactness and reduce the weight of the detector. In the next year we will assemble the
first prototype of the detector. This means the realization of the mechanic assembly for
the Micro Channel Plate and the optic fibers tapered APS. After laboratory evaluation
tests we plan to investigate the scientific capabilities of the detector attaching it at the
91cm telescope of Serra La Nave.
Within this activity a request for ”patent” has been deposited at the local Patent
office (Camera di Commercio di Catania) named: ”A photon counting system based on
CMOS-APS detector”, which claims a count rate much higher (5 to 10 times) than systems
presently available.
67
Figure 2.39: Block diagram of the CMOS-APS photon counting system
2.5.2.3
SPAD detector
SPAD is a p-n junction biased above the breakdown. In this operative condition a holeelectron pair, generated in the depletion layer causes an avalanche, measurable as a current. The diode works as a single photon detector with an infinite gain. The current flows
in the diode until the drive circuit, called active quenching circuit (AQC), turns off the
polarization for a dead time, defined hold off time, and then restores it. In this way the
SPAD is ready for another event. This turn off time depends on the quality of the SPAD.
This activity is carried out since 2001 in collaboration with R&D office of ST microelectronics (STM). During the past year we have measured the characteristics of several
devices produced by STM and in particular, quantum efficiency, dark counts, linearity and
after pulsing (Cosentino et al. 2003b, Proceedings of workshop on ”Scientific detectors for
astronomy”, Waimea, Hawaii, in press). We found that the quantum efficiency, measured
in the the range 350-1050 nm, is typical of a silicon based detector and shows a peak
of about 60% at 550 nm for 100µm diameter devices (Di Franco et al. 2002, Technical
Report ST Microelectronics). Also, as shown in Figure 2.40, it depends on the polarization voltages. Dark counts increase with the bias voltage because the higher electric field
increases the probability of avalanche and the depletion volume. After pulsing depends
on the following phenomenon: during the avalanche, some carriers can be trapped in the
depletion layer and released after a time delay. If this time delay is greater than the
hold-off time, the carrier generates an avalanche named ”after pulsing”. To reduce the
after pulsing effect, the hold-off time had to be increased although this reduces the count
rate. Both causes of dark counts depend on the defects in the depletion volume and can
be reduced with a cleaner fabrication process. Dark counts are measured at 20◦ C, with
a hold-off time of 360 ns that reduces the after pulsing effect. Furthermore, during the
current year we have designed and realized a new active quenching circuit with improved
performances which will be tested next year. For the next year we also plan to characterize two arrays of 5 X 5 elements, with pixel size 20 and 40 µm in diameter, developed by
ST Microelectronics.
68
CHAPTER 2. RESEARCH
Figure 2.40: Quantum Efficiency of SPAD devices with diameter increasing from 10 to
100µm
2.5.3
Collaboration with Industries
As the development of new technology is a fundamental activity of the group the interaction with industries is strategic for the fulfillment of this objective. During 2002 the
group has started and continued collaboration with three main industries:
• The ST Microelectronics for the SPAD project within which the group is designing
and testing a new active quenching circuit to evaluate astronomical applications.
• The LABEN (a firm of Finmeccanica group) italian space industry leader, with the
aim to join this firm as partner in projects for the realization of space mission payloads. Within this collaboration during 2002 COLD researchers have given a series
of lectures attended by members of the research staff of LABEN. The subject of
the lectures was the CCD detector starting from the basic principles up to the most
advanced topics. The front-end electronics and the measurements of its main characteristics were also covered. The theoretical lectures were followed by laboratory
activity at our characterization facility.
• The XILINX Industries, a firm world leader in the production and programming of
FPGA devices. This collaboration will allow us to obtain important know-how on
FPGA devices. During 2002 M. Belluso had a stage course at the XILINX factory
in Dublin, where he was able to use the last version of APS programming software
before the official release.
2.5.4
Support for CCD Cameras and control systems
The activity of the group for the support and improuvement of the OACt CCD cameras
has continued as follows:
69
Figure 2.41: Response of the near UV multilayers filters for the UVISS wide field imaging
camera
2.5.4.1
The CCD camera for the Schmidt telescope at Serra La Nave
COLD reseachers have designed and realized the electronics and the software for the
management of the filter wheel of the CCD camera. The camera will now go through a
phase of commissioning at the telescope. Very preliminary test for the use of a cryo tiger
cooling system have been made for the CCD camera of the spectrograph.
2.5.4.2
Support to solar and stellar observations
The group is involved in the improvement of the performances of the instrumentation for
solar and stellar scientific observations. In particular we are in charge for the maintenance
of hardware and software of CCD cameras and controllers.
2.5.4.3
Support to the Schmidt Telescope at Cima Ekar
We have collaborated in the project managed by the Osservatorio Astrofisico di Padova to
make the Schmidt Telescope 92/67 at Cima Ekar fully automatic. In particular P. Bruno
has developed the user interface for the pointing and the tracking of the telescope and
also the software to manage the focus mechanism and the filter wheel of the CCD camera.
The telescope will be used to study asteroids and object with orbits close to Earth orbit
(NEOs, NEAs etc) and to search for extrasolar planets through the transit technique.
2.5.5
International project collaboration
UV Italian Sky Surveyour. UVISS is a small UV telescope designed for accomodation
on the International Space Station (Bernacca et al. 2000, SPIE Proc., 4139, 199). Our
team is involved, together with the Osservatorio Astronomico di Brera-Merate and the
Istituto di Fisica Cosmica of CNR, in the realization of a wide field camera for near UV
(130-260 nm) and, possibly, far UV (90-115 nm) imaging. Critical components of the
camera are the filters to select the band-passes of interest. The proposed solution will
make use of filters based on the multilayers technique (Scuderi et al. 2000, SPIE Proc.,
4139, 223). During the past year the team has worked on the optical design of the filters
(see Figure 2.41) and has performed few experimental tests on selected coatings. The
70
CHAPTER 2. RESEARCH
results of this work (Conconi et al. 2003, SPIE Proc., in press) are encouraging since they
show that the technique is reliable.
X-SHOOTER. The instrument consists of three separate spectrograph arms for the
UV-Blue, Visual-Red, and near-IR part of the spectrum with a resolution of about
10,000. X-SHOOTER will be built by an European consortium comprising ESO, Denmark, Netherlands and Italy. Within the Work Package on Detector systems, the Catania
group, due to its recognized expertise in the area of detectors and associated electronics
will cooperate with ESO in the characterization of the optical detector systems.
PEPSI. PEPSI is a collaboration of the Astrophysical Institute of Potsdam and of
the Italian Consortium. PEPSI at the LBT will allow investigating the role of magnetic
fields in astrophysics and will be unique among the instruments currently available at
8-10m class telescopes both for its polarimetric capabilities and for the extremely high
resolution. The Catania group will be responsible for the electronics and control software
and for the characterization of the CCD detector for PEPSI. Moreover cooperation on
the polarimeter concept and reduction software is foreseen.
2.6
Computational technologies for astrophysics
INAF Researchers:
Post Doc.:
PhD. Students:
Technical Staff:
2.6.1
V. Antonuccio, U. Becciani
A. Germaná
D. Ferro, A. Romeo
A. Costa, E. Martinetti
Introduction
The development of high performance computing gives a fundamental improvement to the
study of the origin and the evolution of the Universe. This leads to the study of complex
scientific problems, generally using parallel algorithms on massively parallel systems MPP
and SMP systems. However, the availability of these resources produces a large amount of
data that the research needs to manage and analyze. At present, computational resources
needed to run large simulations are available only either in high performance computing sites or using distributed resources. Catania Astrophysical Observatory has an SMP
system, the IBM SP 9076, with 24 processors and 48 Gbyte RAM memory (Fig. 2.42)
principally used for cosmological simulations. This system enables to run very large parallel programs and some parallel codes have been developed by researchers. The Italian
Ministry Istruzione e Ricerca Scientifica (MIUR) has recently financed with 170.000 Euros
the project Supercalcolo e Visualizzazione Scientifica: problematiche astrofisiche attuali
e alta formazione that will allow the OACt to acquire a new IBM Power4 system that
will duplicate the present computational power and will give more than one Tera-Byte
of available disk space for data storage and analysis. The problem of the data analysis
is also a fundamental task of this group, that is involved in a European project for data
analysis using the scientific visualization. The tools AstroMD is a public domain code
that the OACt is developing together with the CINECA VISit Laboratory, using the Virtual Theatre at the Cineca. AstroMD manages multidimensional data from cosmological
simulations, but it can also manage data from observational surveys. The study and
the development of gravitational N-body codes using parallel computing techniques is in
2.6. COMPUTATIONAL TECHNOLOGIES FOR ASTROPHYSICS
71
Figure 2.42: IBM SP 9076.
progress. The tree code has been implemented on three platforms (T3E, Origin and SP)
using the IBM SP system acquired by Catania Astrophysical Observatory. Its final version FLY (Fast Leveled tree n-bodyY code) (http://www.ct.astro.it/fly/) has been made
accessible to the public (open source) and till now is used by more then 50 researchers
all over the world. The project of data analysis proposed by the Catania Astrophysical
Observatory and by CINECA for the years 2001 and 2002 was financed by CNAA. It
will consist in testing some useful techniques and in developing a package of scientific
visualization AstroMD (http://www.cineca.it/astromd) whose first open source version is
already available. The package is based on the Visualization Toolkit (Kitware), which is
a software object-oriented to 3D graphics. AstroMD performs the multi-dimensional and
multi-varied analysis, contains some tools that can visualize clusters, computes specific
quantities (i.e. Correlation functions, Minkowski functionals etc..), analyzes vector fields
and uses the IVR (Immersive Virtual Reality) techniques. The results have been recently
presented at the Europhysics Conference on Computational Physics. The development
of AstroMD has been further financed (Sept. 2001 ) by the European Community which
has approved the Cosmo.Lab project [107] (http://cosmolab.cineca.it). The results have
been presented at several conferences. During the year 2002, in collaboration with University La Sapienza of Rome and ENEA Casaccia, we start the activity Astrocomp, a
portal for astrophysical simulations on a grid of Supercomputers financed by the CNR
Agenzia 2000 (http://www.astrocomp.it). The idea at the basis of our project is to create a national and European portal which allows to create a repository of easily usable
computational codes and a common data base to be made available to the entire national
(and international) community. The original characteristic of the project is that, thanks
to the synergy among the different research units participating to the project, it will allow to share a large, distributed virtual computational resource assembled by the different
platforms made available. More details on these projects are reported in the following
paragraphs.
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CHAPTER 2. RESEARCH
Figure 2.43: Main FLY window.
2.6.2
FLY: a parallel tree-code for cosmological N-Body simulations
FLY is a parallel collision-less N-body code which relies on the hierarchical oct-tree domain decomposition introduced by J. Barnes & P. Hut (1986, Nature. 324, 446) for
the calculation of the gravitational force. Although there exist different publicly available parallel treecodes, FLY differs from them because it heavily relies on two parallel
programming concepts: shared memory and one-sided communications. Both of these
concepts are implemented in the SHMEM library of the UNICOS operating system on
the CRAY T3E and SGI Origin computing systems. On systems like the IBM SP where
these libraries are not available FLY has been modified to use the local libraries. A more
detailed treatment of the parallel computing techniques which have been adopted and of
the resulting performances on different systems can be found elsewhere.
Being an open source project, FLY can and must be modified to suit the particular needs
of individual users. FLY is a dynamically load balanced code based on four main characteristics: it adopts a simple domain decomposition, a grouping strategy and a data
buffering that minimize data communication.
The domain decomposition is based on a fixed distribution of the particles among the
processors: the same number of particles is assigned to each processor. The data structures of both particles and tree are subdivided among the PEs to ensure a good initial
distribution of the load and to avoid any bottleneck while accessing remote data.
FLY uses a grouping strategy with the aim to compute a component of the force to be
applied to all particles inside a grouping cell and to reduce the number of remote access
to build the global force on each particle.
With the data buffering, FLY uses the free RAM portion of each PE to allocate dynamically the tree and the bodies data structures in order to cache remote elements.
All this features make FLY able to run very large cosmological simulations on parallel
systems with high performances: more than 20 · 104 particles per second were computed
using 16 PEs on an IBM SP Power4 1300 MHz at Cineca.
73
Figure 2.44: The main GUI of AstroMD allows to visualize data (Render Window), to
define variables and projects, to control variables and filters and to save results. The side
of the cubic box is 50 Mpc wide. The sample consists of 15000 particles extracted from a
N-body simulation of 16 millions of particles at redshift step z=0, showing the formation
of several structures .
FLY has a graphical Tcl/Tk interface that help the user to create all the parameter
files, excluding the initial condition file.
The main window sets the working directory, the executable directory and will create the
not existing directories. Figure 2.43 shows the main window and the window to set some
parameters.
FLY will be soon included in the Computer Physic Communications Program Library
[31].
2.6.3
Scientific Visualization
In cosmological simulations, one tries to reproduce the formation, evolution and the properties of large scale structures of the Universe. Depending on the scale, one can either
study the properties of single objects, like cluster of galaxies or filaments, or analyse the
statistical properties of the various structures, like the mass function or the correlation
function. These results are finally compared to observations, giving precise indications
on the reliability of the simulated model. Simulated structures generally do not show a
well defined shape or particular symmetries, and they tend to be irregularly distributed
within the computational domain. They analysis requires a powerful 3D representation
allowing fast navigation throughout the structures, selection and zoom capabilities, and
also the possibility of increasing the resolution and accuracy within user-selected regions.
AstroMD [129] provides an effective intuitive way of managing and analysing the large
amount of data produced by numerical simulations as the results from the N-body tree
code [31] which allows to follow the dynamics astrophysical structures in different cosmological frameworks. It can find structures having a not well defined shape or symmetries,
and performs quantitative calculations on a selected region or structure. The whole set
of particles can be visualized but it’s also possible to use a sub-sample of the data, in
order to get a faster and easier visualization. It was implemented a procedure which
select randomly the sub-sample of data. Specific care has been devoted to avoid systematic errors in the selection procedure, so that the sample is still statistically significant.
Different time frames can be shown in a sequence. When particle-representation is used,
the position of particles are interpolated between one time-step and the following. This
74
CHAPTER 2. RESEARCH
Figure 2.45: Formation of clusters of galaxies in the universe, with overdensity of 200
with respect to the background density, visualized by isosurfaces, during the evolution of
a sample of 15000 particles in a cubic box of 50 Mpc.
improves the quality of the ”animation” giving a fluidity otherwise unachievable. Both
the single images and the whole sequence can be saved in bitmap or jpeg format to prepare an animation of the evolution. Enabling the steady-cam, the system can be rotated
in Azimuth and Elevation during its evolution. Zoom-in and zoom-out possibilities are
also offered. The available prototype of AstroMD is being extended with functionalities
for the calculation of quantities of cosmological interest. The most common data format
used in Cosmological simulation, i.e. Tipsy, was included in this software. The basic data
structure is an array of particle structures in three separate arrays for each of the types of
particle used in the simulations: collisionless particles, SPH particles, star particles and
their characteristic properties, as potential energy and temperature. Binary and ASCII
files can be read. While the Universe may be roughly homogeneous and isotropic on the
scale of our horizon, as required by the Cosmological Principle, the distribution of galaxies
in space is decidedly inhomogeneous on scales smaller than this. In order to quantify the
lumpiness of the matter distribution revealed by redshift surveys and to relate this to
models of structure formation, cosmologists employ a variety of statistical tools, the most
common of which is the Power Spectrum. It is defined, in the mathematical language
of Fourier series, in terms of the fluctuation field of matter density. Automatic structure detection and morphology with user-selectable scale and thresholds, to study the
mass density field associated with the particle distribution, was inserted. It distributes
the mass of each particle over a regular computational mesh, by using the Cloud-in-Cell
smoothing algorithm. Gravitational field calculation, solving the Poisson equation, was
implemented too. Moreover, computation of the Power Spectrum of density fluctuations,
as plane waves which evolves independently in linear regime, was implemented. It was inserted the associated two-point Correlation Function too, which is its Fourier Transform,
using HAM as his function estimator, because it is preferable at large scale, for samples
with non uniform density. The clustered zone is inserted in the sampler in which they are.
The plot 2D are shown in another window and is updated when the user points out to
another clustered zone with mouse. The Minkowski Functionals describe the Geometry,
the Curvature and the Topology of a point set. They provide a complete family of morphological measures, which are ”robust” for small samples and independent of statistical
assumptions of the points set. In fact, considering the set of points in 3D space, supplied
by galaxies of a cluster of galaxies, and decorating each point with a ball of radius r,
the tool measures the size, shape and connectivity of the spatial pattern formed by the
75
Figure 2.46: The Power Spectrum of a spherical sub-sample of a whole set of points from
a LCDM model simulation at z=0.
Figure 2.47: Calculation of the Correlation Function of the same model.
76
CHAPTER 2. RESEARCH
Figure 2.48: Minkowski Functionals of a LCDM simulation.
union set of these balls. These characteristics change with the radius r, which may be
employed as a diagnostic parameter. It was inserted a group finding algorithm, known
as Friends-of-Friends, that involves searching around each sample galaxy for companions
close in distance. A particle belongs to a friends-of-friends group if it is within some
linking length of any other particle in the group. User must set two parameters: the
maximum distance among particles forming clustering and numMembers, the minimum
number of clustered particles. At last, FoF cancels all groups whose members are less
than numMembers. It was implemented the calculation of the centre of mass of each
group, the number of components of groups and the radius of each group. The graphical
output contains the grouped particles. The centre of mass of each group identified by
ball with radius as clustered group radius. In another window is displayed the plot of the
fraction of grouped particles versus the number of components of the groups. When the
parameters are changed by user, FoF updates all its outputs.
2.6.4
Grid Computing
Astrocomp is a project developed by the Astrophysical Observatory of Catania, University of Roma La Sapienza and ENEA, and financed by the CNR.
The project goal is to build a web-based user-friendly interface which allows the international community to run some parallel codes on a set of high performance computing
(HPC) resources. There’ s no need for specific knowledge about Unix commands and Operating Systems. Astrocomp makes some CPU times, on large parallel platform, available
to the referenced user .
Astrocomp is a portal which creates a repository of easily usable computational codes
and a common database available to the community. The Astrocomp server is based on
a PHP-MySQL environment Choi, W. et al. (PHP 4 Developper Guide, 2000, Ulrico
Hoepli Editor). Registered users have a grant for HPC systems available to the portal
and can run all the astrophysical codes of the portal. They can easily prepare jobs and
submit them remotely. The portal allows the user to know in real time the job status
77
Figure 2.49: The Astrocomp Portal (http://www.astrocomp.it).
and hardware information of an HPC system like CPU usage, memory and queue status.
Astrocomp looks like a sole interface for users wishing to run parallel codes included in
the portal; it hides HPC complexity creating a common user level.
Astrocomp runs on Apache-Advanced Extranet Server Eilebrecht, L. et al. (Apache Web
Server, 2002, MITP-Verlag GmbH, German): this allows you to set up connections with
enormous numbers of authorized users, without bogging down the server.
The authorized user can access to his area. Astrocomp, who can receive real time information like CPU and memory usage from hardware resources, builds on demand report
pages through PHP code. The user can take a look to the hardware status and choose an
available or free platform. The PHP code allows us to build easy-to-read report pages.
The user can choose a code and a platform to run his job, he will compile some forms
specifying the parameters and all the variables involved in the job. The complete job
history for each user is stored in the MySQL database, so he can easily find his past
parameters collections and simply modify them. After that Astroadmin, who owns all
the sources codes, builds the input files and shell scripts, generates boundary conditions
in accordance to the particular code and platform, compiles and submits remotely the
source code. After job completion the PHP code allows the user to obtain a graphical
representation of output data (this is useful for a quick look analysis); after that he can
download every output file of his job. A constant management of software packets and
the PHP code versus most cost common security bugs and attacks like buffer overflows
and common exploits is actually one of the goals of the project.
The goal of the project is to manage a grid of HPC. We will use an infrastructure like
Globus in order to create a middleware over the hardware resources. The Globus Project
is a research and development project focused on enabling the application of Grid concepts to scientific and engineering computing. The Grid refers to an infrastructure that
enables the integrated, collaborative use of high-end computers, networks, databases, and
scientific instruments owned and managed by multiple organizations. A Grid provides
some abstractions and concepts that let applications access across distributed area networks.
78
2.6.5
CHAPTER 2. RESEARCH
Conclusion
The Astrophysical Observatory of Catania will continue and expand all the above mentioned activities also using the new financed project of the MIUR.
The Scientific Visualization will be enhanced also considering some aspects related to
low cost new technologies for immersive visualization; the FLY project will include new
features for the integration of the code with hydrodynamical codes like FLASH. Gridbased projects will be also developed jointly to CINECA for the extension of Astrocomp
functionalities as a Globus-based portal. OACt MPP computing systems will be linked
to the INFN Grid, with an agreement actually in progress, that will allow the OACt to
include computing facilities in the INFN Grid.
Chapter 3
Projects and Collaborations
3.1
Space projects
World Space Observatory/UV Telescope. Activities related to the implementation and
phase A study of the World Space Observatory/Ultraviolet (WSO/UV) telescope have
been carried out at Catania Observatory. WSO/UV is a project based on a fully open
international collaboration, which is meant to provide advanced observing capabilities
in the ultraviolet (UV) range [55, 70]. The WSO/UV satellite is planned to be a 1.7m telescope operative in the classical UV (from 115 nm to 310 nm), equipped with a
medium/high-resolution plus a long-slit low-resolution spectrograph, high-sensitive and
high-resolution UV cameras and an optical camera. Its launch is planned for 2007, and
it will be finally operated at the Lagrangian point L2 of the Sun-Earth system, where it
should operate for 5 (+5) years. A multinational Phase A study is presently in progress
in several countries (e.g. Russia, Germany, China, UK, Spain, Italy, Israel, etc.) where
National WSO/UV Working (NWWG) groups have been formed, under the coordination
of the WSO/UV Implementation Committee (WIC). Italian scientists have participated
in the WSO/UV project from its beginnig. Specifically, M. Rodonò (Catania University) represented the Italian NWWG till september 2001 in the WIC. After September
2001, I. Pagano, as coordinator of the Italian NWWG, is the Italian representative in
the WIC. The Italian NWWG is formed of about sixty members among astronomers and
technicians, belonging to eleven Italian research institutes and two Italian industries operating in the field of space tecnologies. Since December 2001, G. Bonanno has joined
Brosch (Wise Obs. Israel) as WSO/UV focal plane manager. There are six astronomers
from Catania Observatory involved in the project up to date. Specifically, in 2002, I.
Pagano has participated to the WIC meetings (May 2002 in Moscow, Russia, and Dec
2002 in Tübingen, Germany), and has coordinated the NWWG to plan the contribution to WSO/UV from the Italian Institutes and aero-spatial industries (Alenia, Galileo
Avionica, and Laben), and to present it to the Italian Space Agency in November 2002
to get its support [78]. G. Bonanno, coordinated the WSO/UV focal plane meeting held
in Moscow in May 2002, and participated to the focal plane design and imagers definition.
COROT space mission. Reasearchers at Catania observatory has continued the collaboration with other scientists in Europe for the preparation of the COROT space project.
COROT is a space experiment dedicated to ultra-high precision, wide-field, relative stellar photometry, for very long continuous observing runs on the same field of view. It
79
80
CHAPTER 3. PROJECTS AND COLLABORATIONS
has two main scientific programs working simultaneously on adjacent regions of the sky:
1) asteroseismology, and 2) search for extrasolar planets. Specifically, Busà, Cutispoto,
Messina, and Pagano have monitored a selection of primary targets for the asteroseismology program with the 91-cm telescope of the Observatory to evaluate the level of
magnetic activity in these stars and their rotation periods by analyzing high-resolution
spectra (R ∼ 20, 000) in the region of Ca II H & K lines. The reduction and analysis of
the data collected is in progress.
In the mean time, theoretical work has been carried out by Lanza, Pagano and collaborators at Catania university and at the Laboratoire de Astrophysique de Marseille
(France) to address the influence of stellar activity on the detection of planetary transits
[76].
A contribution to the selection of possible COROT additional programs in the field of
stellar activity has been given by I. Pagano and collaborators [77].
GAIA space mission. A contribution to the GAIA Radial Velocity Spectrometer (RVS)
optimization study has been given by Pagano and Busà. GAIA (http://astro.estec.esa.nl/GAIA/) has been selected as a forthcoming ESA Cornerstone mission and it is designed
to obtain extremely precise astrometry (in the micro-arcsec regime), multi-band photometry and medium/high resolution spectroscopy for a large sample of stars. In particular,
GAIA spectroscopy will be obtained over the 8480-8750 Å wavelength range, centered on
the near-IR CaII triplet and the head of the Paschen series, where also abundant FeI, SiI,
MgI, NI and TiI lines cluster. The spectral resolution is currently foreseen to be around
20,000 [97, 120].
UV Italian Sky Surveyour (UVISS). It is a small UV telescope designed for accomodation
on the International Space Station [4]. The Catania technological team and G. Bonanno,
S. Catalano, A. Lanzafame, Pagano, Rodonò and Scuderi are involved, together with the
Osservatorio Astronomico di Brera-Merate and the Istituto di Fisica Cosmica of CNR, in
the design and realization of a wide-field camera for near UV (130-260 nm) and, possibly,
far UV (90-115 nm) imaging. Critical components of the camera are the filters to select
the band-passes of interest. The proposed solution will make use of filters based on the
multilayers technique (Scuderi et al. 2000). During the past year the team has worked on
the optical design of the filters (see fig. 2.41) and has performed few experimental tests
on selected coatings. The results of this work (Conconi et al 2003) are encouraging since
they show that the technique is reliable.
SoHO/UVCS and SHARP. Spadaro and Ventura continued their involvement in the
SoHO/UVCS project as witnessed by the work described in Sect. 2.1. Moreover, Spadaro
has been recently appointed Responsible for the scientific coordination of the space experiment SPECTRE (i.e., Spectroheliograph for the Transition Region, the P.I. of which
is E. Antonucci from INAF-Turin Observatory) a segment of the Solar and Heliospheric
Activity Research and Prediction Program (SHARPP) having as P. I. R. Howard from
Naval Research Laboratory - Washington. SHARPP is a NASA mission developed in
the framework of the program ”Living with a star” and is to be launched in 2007. The
experiment SPECTRE is a contribution from the Italian solar physics community and it
is devoted to the study of the solar transition region, the interface separating the solar
chromosphere from the corona from which most of the solar EUV emission is originated
and the site of remarkable dynamic phenomena affecting the outer atmosphere of the
3.2. NATIONAL AND INTERNATIONAL PROJECTS
81
Sun. In addition to Spadaro, also the other solar physicists of Catania Observatory and
University are getting involved in the project.
3.2
National and international projects
The research activity at Catania Astrophysical Observatory is going on in the framework
of a number of national and international projects and collaborations, the most important
of which are:
REM. M. Rodonó, G. Cutispoto, E. Martinetti, S. Messina and S. Sardone have collaborated on the design of the REM automatic telescope for near-infrared spectroscopy,
devoted to the observations of Gamma Ray Bursts, detected by the NASA SWIFT satellite. REM is a small rapid reaction automatic telescope dedicated to monitor the prompt
afterglow of γ-Ray Burst (GRB) events. One of the most important characteristics of this
instrument is the fast pointing system which will enable the detection of the GRBs [Zerbi
et al. Astronomische Nachrichten, 2001].
WSO/UV. The World Space Observatory is an international project which involves
several countries in the realization of a space telescope optimized for ultraviolet observations. The project is in the feasibility study phase and the group is involved in the
realization of an imaging camera and detectors. I. Pagano, coordinator of the Italian
Working Group, has represented the Italian community at the WSO/UV Implementation
Committee [78].
COROT. I. Pagano has also worked on the COROT project, coordinating the Italian
group involved in stellar activity programs [77]. A.F. Lanza and M. Rodonó have discussed
the role of magnetic activity in the detection of oscillations in solar type stars by COROT
[17].
X-SHOOTER. X-SHOOTER is a high-efficiency medium resolution spectrograph which
will allow simultaneous coverage of the whole spectral range from the UV (300 nm) to the
near IR (1.9 micron). The instrument consists of three separate spectrograph arms for
the UV-Blue, Visual-Red, and near-IR part of the spectrum with a resolution of about
10,000. X-SHOOTER will be built by an European consortium comprising ESO, Denmark, Netherlands and Italy. Within the Work Package on Detector systems, the Catania
group, due to its recognized expertise in the area of detectors and associated electronics
will cooperate with ESO in the characterization of the optical detector systems.
PEPSI. PEPSI is a fibre-fed spectropolarimeter and high-resolution spectrograph for
LBT, that takes full advantage of the binocular nature of the telescope. In the polarimetric mode it will allow observing simultaneously circular and linear polarization at
high-resolution (R = 80,000), while in integral light it will reach an even higher resolution
(up to 300,000). PEPSI is a collaboration of the Astrophysical Institute of Potsdam and
of the Italian Consortium. PEPSI at the LBT will allow investigating the role of magnetic fields in astrophysics and will be unique among the instruments currently available
at 8-10m class telescopes both for its polarimetric capabilities and for the extremely high
resolution. The Catania group will be responsible for the electronics and control software
and for the characterization of the CCD detector for PEPSI. Moreover cooperation on
the polarimeter concept and reduction software is foreseen.
A complete list of participation in projects is the following:
82
Acronym
APT/2-80cm
AVES
COROT
EUSO (ex AirWatch)
REM
PEPSI
SOHO
SPAD
TNG
UVISS
WSO
Diamante Project
Project Title
Automatic Photometric Telescope with CCD camera
Adaptive optics Visual Echelle Spectrograph: intermediate
dispersion spectrograph for VLT (ESO) / LBT, with
adaptive optics. Phase A
COnvection ROtation and planetary Transits, CNRS-ASI
-ESA
Space-born telescope for EECR study (Extreme Energy
Cosmic Ray), ASI-NASA
Robotic telescope (Rapid Eye Mount) GRB detection in
the NIR band
Potsdam echelle Polarimeter Spectrograph instrument
SOlar and Heliospheric Obs., UVCS Spectrograph, NASAESA
Single Photon Avalanche Diode
Telescopio Nazionale Galileo (technical plant, detectors
imaging systems, polarimetric module on SARG)
UV telescope for the International Space Station
World Space Observatory, a large UV space mission
Development of detectors based on CVD diamonds
Table 3.1: Projetcs titles
3.3
Staff involved in projects
Name
Project
Becciani U.
Bonanno A.
Bonanno G.
TNG (archiving software group )
COROT (WG Seismology)
TNG ( Imaging and SARG group)
UVISS (Detector for the imaging camera)
AVES ( CCD camera , controller)
PEPSI (Control electronics and CCD)
SPAD (Electro-optic characterization)
WSO (Detector coordination)
AVES (CCD camera, controller)
TNG (Imaging group, SARG, polarimetric module)
UVISS (Detector for the imaging camera)
Belluso M.
Bruno P.
3.3. STAFF INVOLVED IN PROJECTS
83
Name
Busá I.
Calı́ A.
Catalano S.
Cosentino R.
Cutispoto G.
Di Benedetto R.
Di Mauro M.
Gentile G.
Frasca A.
Lanza A. F.
Leone F.
Martinetti E.
Messina S.
Pagano I.
Sardone S.
Scuderi S.
Spadaro D.
Ventura R.
Project
AVES ( CCD camera , controller)
PEPSI (Controls software )
COROT (WG Stellar activity, and Ground Support)
APT/2-80cm (Data archiving and reduction)
TNG (Imaging group and SARG)
TNG (SARG polarimetric module)
UVISS (Science team, imaging camera)
AVES (Science team)
PEPSI (OACt chair person)
TNG (Imaging group, SARG)
AVES (CCD camera, controller)
REM (OACt chair person)
EUSO (Calibration)
COROT (Seismology WG)
GONG
TNG (Polarimetric module)
APT/2-80cm (Focal plane mechanics)
APT/2-80cm (Archive and data reduction)
TNG (Polarimetric module project)
PEPSI (Polarimetry, data reduction)
REM (Mechanics, electronics and test)
APT/2-80cm (Software e installation)
APT/2-80cm (Archive and data reduction)
COROT (WG stellar activity and Ground support)
REM (Science team)
UVISS (Science team)
WSO (Italian PI, Science team)
REM (Mechanics, electronics and test)
APT/2-80cm (Mechanics, optics supervisor)
TNG (Imaging group SARG)
UVISS (Imaging camera,mirrors,filters)
AVES (CCD camera)
Diamante Progect (Detector)
SOHO ( UVCS, Co-I)
SOHO (UVCS, Co-I)
84
Name
Project
COROT (WG Seismology)
Table 3.2: OACt researchers Projects
3.4
Collaborations
In the scientific context of the researches carried out at Catania Observatory several
collaborations with single scientists and Institutions are going on as listed below:
Solar Physics:
- Big Bear Solar Observatory, Big Bear City, CA 92314, USA: V.B. Yurchyshyn
- Dip. Astronomia Univ. Firenze, Firenze: G. Noci
- Dip. Di Fisica Univeritá di Roma “Tor Vergata”, Roma: F. Berilli
- Dip. Scienze Fisiche e Astronomiche, Univ. di Palermo, Palermo: G. Peres
- INAF Osservatorio Astronomico di Palermo, Palermo: S. Orlando
- INAF Osservatorio Astronomico di Torino, Pino Torinese (TO): E. Antonucci
- Institut d’Astrophysique Spatiale, Parigi (Francia): J.C. Vial, P. Lemaire
- Mathematical Science Dept., St Andrews University, St. Andrews, KY16 9SS United
Kingdom: E.R. Priest
- Naval Research Laboratory, Washington (DC, USA): S.K. Antiochos, et al.
- Themis, France: C. Briand
Stellar Physics:
- Armagh Observatory, Armagh (North Ireland): C.J. Butler, J.G. Doyle
- Astrophysikalisches Institut Potsdam (Germany): K.G. Strassmeier, G.Rüdiger, D.
Elstner, Th. Granzer
- Astron. Institute, Potsdam (Germany) : K. Strassmeier, et al.
- Canada-France-Hawaii Telescope Corporation: E. Magnier, E. Ménard
- Complejo Astron’omico El Leoncito (Argentina): S. Malaroda
- Catholic University of America (IACS), Washington (DC, USA): R.D. Robinson
- Dept. of Physics and Astron., College of Charleston (NC, USA): J.E. Neff
- Dept. of Physics and Astronomy, Rutgers University, (NJ, USA): M. Gagné
3.4. COLLABORATIONS
85
- Dip. Scienze Fisiche e Astronomiche, Univ. di Palermo, Palermo: G. Peres
- Goddard Space Flight Center, Greenbelt (MD, USA): HST/STIS Team
- Ege University Observatory, Bornova, Izmir, Turchia: C. Ibanoglu, S. Evren
- European Southern Observarory, Garching bei Munchen (Germania): L. Pasquini
- European Southern Observarory, Santiago del Cile (Cile): M. Kurster, S. Bagnuolo
- Istitute d’Astrophysique de Paris, Paris (Francia): M. K. Andre’
- Inst. d’Astrophys. Spatiale, Univ. Paris XI, Orsay (Francia): P. Gouttebroze
- Istit. di Radioastronomia del CNR, Noto (SR): C. Trigilio, G. Umana
- Institute for Astronomy, University of Hawaii : E.L. Martı́n
- Joint Institute for Laboratory Astrophysics, Boulder (CO, USA): J.L. Linsky, A.
Krishnamurthi
- Johns Hopkins University, Baltimora (MD, USA): L. Bianchi, P. Sonnentrucker
- Laboratoire d’Astrophysique de Marseille (France): P. Barge, M. Deleuil
- Lockheed Palo Alto Research Co., Palo Alto (CA, USA): B.M. Haisch
- National Astronomical Observatory, Sofia (Bulgaria): N. Markova
- National Optical Astronomical Observatory, Tucson (AZ, USA): J. Valenti
- Observatoire de Grenoble: C. Dougados
- Observatoire Midi-Pyrènès (Francia): J. F. Donati
- Obs. Astronomique, Univ. Strasbourg (France): R. Freire-Ferrero, A. Fresnau, J.
Guillot
- INAF Osservatorio Astronomico di Brera, Merate (MI): G. Chincarini, G. Tagliaferri, L. Pastori, E. Antonello, L. Mantegazza, + REM Group
- INAF Osservatorio Astronomico di Capodimonte, Napoli: E. Covino, J Alcalá
- INAF Osservatorio Astronomico di Palermo, Palermo: R. Pallavicini, A. Maggio
- INAF Osservatorio Astronomico di Roma: F. D’Antona, C. Maceroni
- INAF Osservatorio Astronomico di Torino: M. Villata, C. M. Raiteri
- Observatoire de Paris: A. Baglin, et al.
- Space Telescope Science Institute, Baltimora (MD, USA): N. Panagia
- Special Astrophysical Observatory of the Russian (Russia): D.N. Monin
86
- Theoretical Astrophysics Center, Aarhus (Danimarca): J. Christiansen-Dalsgaard,
F. Pijpers, H. Kjeldsen
- Univ. Federale del Rio Grande du Norte, Natal (RN, Brasile): R. de Medeiros
- University of Chicago, Chicago (IL, USA): R. Rosner
- University of Southampton (UK): P. Maxted
- University of Sussex, Department of Physical Sciences (UK): R.P. Fender, S.K.Yerli
- University of Toronto (Canada): G. A. Wade
- University of Villanova, Villanova (PA, USA): E.F. Guinan, C. Ambruster
- University of Western Ontario (Canada): J. D. Landstreet
- Universitat Wien (Austria): M.J. Stift
Chemically Peculiar Stars:
- Complejo Astronomico El Leoncito, San Juan (Argentina): S. Malaroda
- Istit. di Radioastronomia del CNR, Noto (SR): P. Leto, C. Trigilio, G. Umana
- NASA InfraRed Telescope Facility, Honolulu (HI, USA): W. Vacca
- South African Astronomical Observatory, Cape Town (Sud Africa): P. Martinez
- University of Cape Town, Cape Town (Sud Africa): D. Kurtz
- University of Toronto, Toronto (Canada): G. Wade
- University of Wien, Vienna (Austria): S. Bagnulo, M. Stift
Experimental Astrophysics and Solar System:
- Dept. of Astronomy, Ohio State Univ., Columbus (OH, USA): D. M. Terndrup
- Dept. of Astronomy, Univesrsity of Charlottesville,Virginia (VA, USA): R.E. Johnson, R. Baragiola
- Earth and Space Sci. Dept., NY State Univ., Stony Brook (NY, USA): F. Walter
- German Aerospace Center, DLR, Berlin: Ljuba Moroz
- INAF Osservatorio Astronomico di Roma: Elisabetta Dotto
- INAF Osservatorio Astrofisico di Arcetri, Firenze: P. Caselli, M. Walmsley
- INAF Osservatorio Astronomico di Capodimonte, Napoli: L. Colangeli,J. Brucato,
V. Mennella
- INAF Osservatorio Astronomico di Cagliari, Cagliari: G. Mulas
3.4. COLLABORATIONS
87
- INAF Osservatorio Astronomico di Roma, Roma: B. Nisini
- Max Plank Inst. fur Kernphysik, Heidelberg (Germania): J. Kissel
- NASA-AMES Laboratory (CA, USA): A.G.G.M. Tielens, Y. Pendleton, D. Cruikshank
- University of Catania, Department of Chemistry: G. Compagnini.
- University of Lecce, Department of Physics: V. Orofino, A. Blanco, S. Fonti
- University of Valencia, Spain: M. Satorre, O. Gomis, M. Domingo
Galaxies and Cosmology:
- Inst. of Astron., Univ. of Edinburgh (UK): E. van Kampen
- Lebedev Instit. for Theoretical Physics, Mosca (Russia): V. Lukash et al.
- Università di Copenhagen (TAC), Copenhagen (Danimarca): J. Sommer Larsen
- Università dell’ Insubria, Como: A. Treves
- Università ”La Sapienza”, Roma: E. Massaro, R. Nesci
- INAF Osservatorio Astronomico di Torino, M. Villata
Image Detectors and image Processing:
- CARSO (Center for Advanced Research in Space Optics), Trieste: R. Stalio
- Dipartimento di Fisica, Università di Firenze, Firenze: P. Spillantini
- English Electric Valve, Chelmsford (UK): P. Jorden
- European Southern Observarory, Garching bei Munchen (Germania): J. Beletic
- Istituto di Fisica Cosmica del CNR, MIlano: M. Uslenghi
- INAF Osservatorio Astrofisico di Arcetri, Arcetri (FI): E. Pace
- INAF Osservatorio Astronomico di Brera, Merate (MI): R. Citterio
- INAF Osservatorio Astronomico di Padova, Padova: R. Gratton, F. Bortoletto
- INAF Osservatorio Astronomico di Palermo, Palermo: R. Pallavicini
Others:
- CINECA, Casalecchio di Reno (Bo): G. Erbacci e R. Ansaloni (Calcolo ad Alte
Prestazioni), C. Gheller e L. Calori (Visualizzazione Scientifica)
- Ottica Marcon, S. Donà di Piave (VE): progetto APT/2-80cm
88
Chapter 4
Facilities and Services
4.1
Buildings
The refurbishment of the main building of the Osservatorio Astrofisico was completed. It
was financed by the Università degli Studi di Catania, which is the owner of the building,
and by the Observatory. The plan and the direction of the works were under the responsibility of the deputed Office of the University Technical Support Service. The Technical
Support Office of the Observatory has been also deeply involved during all the phases of
the works to warrant a proper consideration of all the specific requirements for the disactivation and re-activation of the installations and plants as well as for moving around the
offices and various facilities from the working areas.
A new high-vacuum facility has been planned for mirror allumination at the mountain
station M. G. Fracastoro and required permissions have been granted by the deputed
public authorities. A public announcement to find and select the prime contractor will
be issued at the beginning of 2003.
The plan for the re-structuring of the building housing the automated telescopes at
the M. G. Fracastoro station was approved by the deputed public authorities and by the
Parco dell’Etna who recommended the implementation of a scheme considting of three
folding domes in order to minimize the environmental impact.
The main characterstics of the three domes were specified in order to allow a fully
automated operation of the telescopes and the German firm Halfmann Teleskopetechnik
GmbH of Amburg was informally contacted for further advice. They built similar dome
structures for ESO at the observatory on the top of Mt. Paranal. We plan to host in the
new building also a small telescope dedicated to educational and outreach activities in
addition to the automated telescopes.
The roof of the main building at the M. G. Fracastoro mountain station was damaged
by the snow and ice during winter 2001-2002. Having been built more than thirty years
ago, it requires now an extra-ordinary maintainance work for which a specific plan has
been already prepared by the Genio civile.
89
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CHAPTER 4. FACILITIES AND SERVICES
4.2
Training and courses attended by the staff members
A specific training activity was devoted to the staff on duty in order to update and
increase their command of the mostly used software systems and packages. Specifically,
an IDL advanced course was organized for the scientific staff and a course for advanced
users of LINUX mainly for the technical and library staff. Some specific courses covering
catalogation and searching softwares and the author’s right in scientific publication were
attended by the librarians. All the courses and training activities were also open to
interested people belonging to the research and teaching staff of the University as well as
to PhD students. The detailed list is as follows:
• Banche dati e ricerche bibliografiche AIB Sicilia: Catania, 6 Marzo 2002
• Diritto d’autore- AIB Sicilia: Catania 19-20 Giugno 2002
• Training Catalogazione MILLENNIUM CBD Universita CT: Catania 1-2 Ottobre
2002
• La nuova disciplina del sistema pensionistico. Presentazione ed utilizzo applicativo
Pensioni (S7) a seguito convenzione INAF-INPDAP Roma 8-12 Aprile
• Scuola Nazionale di Tecnologie Astronomiche - Napoli 23 28 Settembre 2002
• Corso IDL avanzato tenuto presso l’ OACt da un responsabile della RSI Italia
• Corso LINUX utente avanzato MFH: Catania 2-4 Dicembre 2002
• Corso Xiling, Dublin 2-20 december 2002
• Corso su bilancio di cassa con programma CIA 1-3 December 2002, Cineca, Bologna
4.3
Acquisition of new instrumentation and facilities
The enhancement and the renewal of the scientific facilities have gone on in 2002 according
to the annual programme. Moreover, using the saving on expenses obtained in the previous
balances, it has been possible to get new facilities. The most important ones acquired in
the course of 2001 are:
• Upgrade of the ion implanter of the LASP, made by the firm Danfysik;
• a new automated photometric telescope (APT80/2): the mechanics and optics have
been completed by the firm Marcon;
• a linear lathe made by Mexim to be installed in the new mechanical workshop;
• a criogenic system by Cryotiger for the CCD camera of the REOSC spectrograph;
• a new vacuum dry pump by Triscroll;
• a Shack-Hartmann wave-front analyzer for the alignment of telescope mirrors;
4.4. LIBRARY
91
• a new CCD detector for the Raman spectrograph;
• a CCD detector (EEV 05-30) for solar observations;
• a CCD detector (EEV 42-40) for the CCD camera of the APT80/2
4.4
Library
Scientific supervisor:
Staff:
R. Ventura
A. Mangano, M. Calı̀, G. Caripoli, D. Domina, D. Recupero,
G. Santagati.
The library collection of Catania Astrophysical Observatory presently includes 10303
volumes, 126 journal titles, 234 antique (see Fig. 4.1 and 4.2) volumes and a number
of audio-video material. The library content is mainly specialized for Astronomy and
Astrophysics, but two significant sections are also devoted to General Physics and Mathematics. Moreover, a special section, dedicated to education is continuously updated with
cd-roms and video-tapes. The library is open to astronomers, technicians and staff of the
Observatory and to teachers belonging to the Departments of the Catania University as
well as to researchers and University students of several institutions and faculties, and to
all interested visitors (by permission). Opening hours: from Monday to Saturday, from
8:15 to 13:45 and on Monday, Wednesday and Thursday from 14:30 to 17:30. Services:
Loan; interlibrary-loan; document delivery service.
Figure 4.1: Library historical section, Secchi (1875): A solar spot drawing taken from
“Le soleil: premiere partie” by Angelo Secchi, Deuxième édition, revue et augmentée,
Imprimerie de Gauthier-Villars, Paris 1875.
92
Figure 4.2: Library historical section, Tacchini (1888): A solar eclipse drawing taken from
“Eclissi totali di sole” by Pietro Tacchini, Tipografia Eredi Botta, Rome 1888.
Due to the refurbishment work inside the Observatory buiding, the reading room was
unaccessible and some reading space was provided inside the main library hall. The
routine maintanance activity were reduced to essential and urgent tasks in consideration
of the limited space available.
Acquisitions and inventory (G. Caripoli, D. Domina, M. Calı́). The saving imposed
on the Observatory expenses limited the funds avalaible for the library. Therefore a total
amount of 73.000 euros was spent during 2002 to buy books and journal subscriptions.
The reduction of the fundings implied a remarkable decrease in the number of renewed
subscriptions for the year 2003. The selection of the renewed subscriptions was made by
taking into account the indication of the research and technical staff as well as the availability of the journals through other observatories or institutes belonging to the national
library network Archivio Collettivo Nazionale Periodici (ANCP). The on-line services provided by the Centro Biblioteche e Documentazione of the University of Catania granted
access to several on-line journals and further helped to reduce the cost of subscriptions.
In general, the reduction of costs for every single acquisition was also made possible by
the comparison of on-line offers and by the services offered by the library consortiums
(ESO, CNR-Bologna, CILEA; CBD- Catania, INAF) which provided free journals in a
mutual exchange regime.
Cataloguing (D. Domina, A. Mangano). New books acquired in 2002 (about 90)
have been catalogued according to descriptive and semantic rules, with the UNIBIBLIO
software. The relative bibliographic control has been made when the records have been
exported to built the web catalogue. The semantic cataloguing has been made using an
4.4. LIBRARY
93
Italian Subject Index (edited in 1999) which refers to that of the Library of Congress and
to the IAU Thesaurus. The new software MILLENNIUM – a new integrated web-based
cataloguing software provided by the University of Catania – has been tested and used for
some limited applications. Journals catalogue (L. Santagati, A. Mangano). The update
of the journals list has been performed following the on-line procedure of the Archivio
Collettivo Nazionale Periodici (ACNP), adopted by the library. In 2002 the on-line service
of document delivery has increased (more than 120 articles required both by the Italian
Observatories and other Institutes partecipating to the ACNP consortium and other interlibrary exchange organizations). This retrieving work required a significant increase of
dedicated time with respect to year 2001.
Historical Archive and Catalogue (D. Recupero and A. Mangano). In the framework
of the national project Specola 2000 which gathers all the Italian Observatories with the
aim of developing and making the historical collections accessible, the Sovraintendenza
Archivistica per la Sicilia committed the inventory of the historical archive to an external
collaborator. The bibliographic part and the correspondence was previously sorted by the
librarians. The joint work of the collaborator and of the Observatory staff librarians led
during 2002 to the completion of the inventory of the historical archive for the period 18651954. It is presently accessible in printed form and contains seven series of documents of
great importance for the history of Catania Observatory. The series of letters has already
been requested for consultation by various users, both internal and external.
Scientific secretariat and Preprints (D. Recupero and L. Santagati). Thirty-eight
preprints have been printed and distributed to 47 Italian and foreign Astronomical Institutes and Observatories. All the preprints were made accessible also through the web site
of the Observatory. Several papers have been linguistically reviewed. The organisation
of the Third Meeting on the Italian Solar Research held in Vulcano in October 2002 was
managed. The proceedings of the international meeting ”Asteroids 20001. From Piazzi
to the 3rd Millennium” were also edited for the Memorie SAIt.
Loan, reference service, electronic information service (D. Domina, A. Mangano, D.
Recupero, L. Santagati, G. Caripoli). The reference service for students and researchers
consists in the search in the local catalogues, both printed and on-line, and other external catalogues using internet facilities. The intense collaboration between the libraries of the other Italian Observatories has enhanced thanks to the CUBAI (Catalogo
Unico Biblioteche Astronomiche Italiane) and ACNP Astronomico projects. Other collaborative links has been established (CIBD Centro di Coordinamento delle Biblioteche
dell’Universitá di Catania and other foreign institutions) in the framework of a more and
more intense inter-library cooperation.
Activity in coordination with INAF. During the year 2002, frequent exchanges and
meeting were held among the librarians of the Italian observatories, coordinated within
INAF. The library staff of Catania Observatory contributed to several significant aspects,
assisted also by an expert in computer science for the development and implementation
of new software for a new national astronomical library service. The development of a
National Library System for INAF has been proposed in order to optimize the available
resourches and made them fully available to the research community. A detailed report
on the library of Catania Observatory was prepared as a first step for contributing to this
project according to the guidelines specified the deputed INAF working group.
94
4.5
Computing Center and local network
Supervisor:
Staff:
P. Massimino
A. Costa, C. Lo Presti, A. Giuffrida
Catania site: The computing center consists of central machines and distributed workstations, running various operating systems:
• Central machines (computing servers):
– SUN Sparc 20 (UNIX) Server and Sun cluster
– Compaq DS10 (Open VMS)
– SG Origin 200 with two processors (UNIX)
– LINUX Cluster based on 5 PCs AMD 1.4 GHz
– IBM 9076-550 SP3 with 24 parallel processors
• Network server:
– PC Linux Suse 7.2 (astrct: DNS, SSH ..., FTP, WEB and the solar image
archives)
– PC MS-WindowsNT (netserver, interactive Web services for astronomy and
library)
– a LAN consisting of 75 personal computers and workstations for the research
staff, technicians and administration staff.
– four laser printers
During 2002 the implementation and reconfiguration of the components which must
guarantee the security of information systems have been continued. New facilities have
been implemented. The problem of security has been among the main issues of this year.
The principal specific activities can be summarized as follows:
• The new firewall Sonicwall Pro 200, supplied with the ”High Availability” software,
was installed and configured. It allows a detailed analysis, both through graphics
and tables, of all the networked activities generated in the Observatory’s LAN and
of those generated in the external WAN.
• A new control system to prevent spamming activities was implemented on the SMTP
server. It consists of two components, MailScanner and SpamAssassin, which seek
for viruses attached to e-mail messages and for spammed messagges, respectively. In
this way, the risk of propagation of viruses through e-mail and of spamming attacks
is largely reduced.
• The computing resources available on the Linux cluster were updated and upgraded
also by including new nodes. One node is exclusively dedicated to mass memory
sharing and to management of the printer queues.
4.6. OPTO-MECHANICAL WORKSHOP AND TELESCOPES’ AUTOMATION
95
• The security level of the remote accesses operated through the new PPP(ISP) server
was increased. In its present configuration, it allows several users to access simultaneously our server by means of four telephone analogical lines operated by the
OACt PBX (switchboard).
OA Catania Web site: The observatory web page is continuously updated. The new implemented resources includes: Minor Planet Electronic Circulars (MPEC) and IAU Circulars,
the access to which is restricted to internal users connecting through the Observatory’s
LAN. The on-line catalogue of the Observatory’s library has been continuously updated
and made available to internal and external internet users. Moreover, the electronic versions of our preprints were made fully accessible through internet in collaboration with the
library and scientific secretariat staff. The new server www.astrocomp.it was configured
for use in the framework of the AstroGrid project.
Solar images on the Web: The images of the Sun acquired during 2002 at Catania Observatory were put on the Web and catalogued in ”web access” mode, thus updating our
solar image web archive. All the images daily collected on the web page are stored in the
archive and are freely accessible.
M.G. Fracastoro station (Serra la nave, Etna): Starting from a feasibility study and the
positive tests performed during 2001, a detailed technical plan was issued for a wireless
connection at 2.4 GHz between the Catania site and the M. G. Fracastoro mountain
station. The connection between the lodge and the nearby ENEL tower on which the
antenna at the M. G. Fracastoro site is going to be located, will be made by means of optical fiber cabling. The necessary authorizations were finally obtained by Parco dell’Etna
for the underground cabling, by Enel for the installation of the antenna, by the Ministero
delle Telecomunicazioni for the frequency allocation, respectively. The firm Software and
Network Consulting is in charge of the implementation of the plan.
Training activities and partecipation to scientific meetings. Fifteen members of the staff
attended the course on Linux held by MHP at the Catania section of INFN. P. Massimino
and A. Costa attended the IV Garr meeting at Bologna and presented a communication on
the new wireless connection between the Catania site and the M. G. Fracastoro mountain
station. The first meeting of the system managers of the Italian Observatories belonging
to INAF was held in Florence and was attended by P. Massimino on behalf of Catania
Observatory. P. Massimino and A. Costa are involved in the project DataGrid, in collaboration with INFN. Moreover, P. Massimino is involved in a project for the scanning and
digitization of old photographic plates belonging to the collection of Catania Observatory.
4.6
Opto-mechanical workshop and telescopes’ automation
INAF staff:
External collaborator:
G. Carbonaro, G. Gentile, M.P. Puleo, E. Martinetti,
M. Miraglia, S. Sardone, P. Bruno
S. Massaro
96
4.6.1
Telescope automation
91-cm Cassegrain telescope: The new software ”Asterix 2000”, installed and commissioned
in 2001 confirmed its stability and operation effectiveness. Its main utilities include:
• on-line catalogue of stars with magnitudes >2, used for the calibration of the telescope
• on-line NGC, IC, UGC, SAO, Messier and GCVS catalogues
• view of the selected field through the images of the DDS catalogue accessible via
internet
• on-line processing of the image acquired from the DSS catalogue
• calculation of the ephemeredes of the solar system objects
The software converting the telescope coordinates into the azimuthal system will allow to
interface the control system to the electronic encoder providing the position of the dome.
Therefore, it will be easier to perform a complete automation of the telescope. The cloche
has been modified to allow the interface with the tracking electronic system. A tracking
software has been developed within the Lab-view environment, using its graphic libraries.
The image acquisition card has been replaced with an updated one which performs the
processing through a 10 bit A/D converter. The effectiveness of this system proved to
be good and it was used for most of the year. The determination of the centroid of the
reference star and the tracking of the telescope are made on a single digitized frame acquired by the intensified camera. The current accuracy of the tracking is about 0.5 arcsec
with corrections typically applied on timescales of 5 s. The accuracy in the tracking may
be improved by using more frames, but a limit is set by the telescope mounting mechanics.
The optical quality of the imagine at the Cassegrain focus was tested by means of a
Schack-Hartmann wavefront analyser. This revealed some anomalies in the mechanical
supports of the primary mirror and a variable misalignment of the secondary mirror due
to the flexions of the telescope tube, which were already qualitatively known from previous tests. Therefore, a feasibility study was undertaken to desing a moveable support for
the secondary mirror and the implementation of a Schack-Hartmann wavefron analyzer
to improve the quality of the image. The best seeing measured at the M. G. Fracastoro
station was of the order of 1 arcsec, hence the improvement of the telescope optical quality
according to the above plan is highly recommendable also in consideration of the foreseen
application of a photometric CCD camera and of the use of an optical fiber of 100 micron
for the spectrograph.
61-cm Schmidt telescope: The project of the mechanical revision has been critically reexamined and updated before starting the operative phase. In particular, a series of tests
showed that it is not possible to use a system based on a double pinion and a brake
for moving the telescope in declination without angular clearance. Moreover, the double
pinion system with an electric pre-loading would require a cooling system of the engines
too complicated for application to a 61-cm telescope. Therefore, the whole system was redesigned considering the user of a brushless torque engine manifactured by ETEL which
4.6. OPTO-MECHANICAL WORKSHOP AND TELESCOPES’ AUTOMATION
97
does not need braking and cooling systems and is capable of operate under a load unbalance up to 100 kg. The design phase was completed and the engine and the encoder have
been commissioned. The controller is similar to that of the Galil system and is thus fully
compatible with the control software Asterix, the standard operation software managing
all our telescopes.
APT-80/1: A fault occurred in the controller was impossible to be repaired because
the necessary electronic components are out-of-stock. A re-design of the whole operation
and acquisition systems is presently carried on, in order to make the telescope operable
with a new control hardware and software no more limited by the MS-DOS operating
system on which the previous one was based.
APT-80/2: The manufacturer Marcon has completed the mechanics and the mirrors [
(figure 3)]. The motion of the telescope, based on brushless engines and on the Galil
controller has been implemented by the staff, following the standard procedure applied
for every telescope at the Observatory. The pointing and tracking operations have been
successfully tested at Marcon by the Asterix 2000 software, thus confirming its reliability
and portability. Pointing and repeatibility accuracy, tested with a laser beam, matches
the constraints requested to the manufacturer. The requirements of the domes, whose
aperture must be compatible with the automatic movement of the telescopes, have been
set and the Halfmann Teleskopetechnik GmbH in Hamburg , which will realize the cover
with folding material, has been contacted. This kind of cover has been already installed
at ESO at Mt.Paranal. The building will also host a telescope for educational activities.
The required authorizations have been obtained by Parco dell’Etna.
4.6.2
Opto-mechanical laboratory
Aluminization: The primary mirror of the 91-cm telescope was re-aluminized, using a new
procedure for evaporating the metal. The reflectivity gain was remarkable in comparison
to the past and a further improvement was obtained thanks to the re-configuration and
alignment of the optical system.
Spectro-polarimetric module: The spectro-polarimetric module for the REOSC echelle
spectrograph mounted at the 91-cm telescope has been successfully tested and the precision of positioning and alignment of the polarizing plate have been checked. An analogue
module, which makes use of super achromatic plate, realized for the high resolution spectrograph (SARG) has been installed at the Telescopio Nazionale Galileo. Since the first
tests we could notice the high quality standards of the system which in agreement with
the characteristics required, has an efficiency of 92 % and 85 % for the linear and circular
polarization respectively.
New off-set guider: The project of the new offset to be mounted at the 91 cm telescope has been completed, the support structure has been built and the software for the
movement of the probe mirror has been installed. It is based on a programmable highprecision controller (10 microns in the positioning accuracy). The system allows to put
the probe mirror in the central position for pointing as well as in four side position for
98
the off-set guidance.
Focal reducer and CCD camera: A focal reducer for the CCD camera was built with
two filter wheels for UBVRI filters. The CCD camera, with a newly conceived Peltier
cooling system, is under construction by the firm Hitech under the supervision of the
detector research group of the Observatory. The camera uses a 1024x1024 CCD with 24
micron pixels; it will have a 10 arcmin field of view and will reach a magnitude 18 with
S/N=100 in 10 min.
Technical installations: The LAN network has been installed in the new building of the
Catania Observatory: new access points have been activated in all offices and working
desks for PhD students. The same network has been installed in the two offices at M.G.
Fracastoro Observatory on Mt. Etna, and the connection with the dome of the 61-cm
telescope has been activated.
4.7
CCD image acquisition
Supervisor:
Research staff:
Technical staff:
G. Bonanno
R. Cosentino, S. Scuderi
M. Belluso, P. Bruno, A. Calı̀, M.C. Timpanaro
The activity of the image acquisition devices is managed by the detector staff, who
performs the maintenance and implementation of new cameras and control systems. The
activity carried out in 2002 consists in the following:
Solar CCD Camera: The old CCD camera implemented ten years ago is still operative
with the acquisition system COLD-WIN with image storage in FITS format, under
the continuous supervision and technical maintainance by the detector group staff.
Moreover, our staff completed the installation of a mechanical device for positioning
and controlling the focus of the lens on the solar spar, adopting a standard device
control system.
Imaging CCD camera for the 61-cm telescope: A new camera, cooled by Peltier effect
cell, was designed and manufactured by the group. The mechanical interface with
the filter wheel was designed by the group and built by to an external manufacturer
(TMA). Its control system is based on a standard set up built by the staff. The
system, including the controller and the kodak CCD, is under final testing.
Imaging CCD camera for the 91-cm telescope: The staff has designed and manufactured a
prototype of a new camera for the 91-cm telescope coupled to the focus reducer. This
camera will be cooled by a three stages Peltier effect cell able to reach temperatures
of −70◦ C. The prototype is under testing as far as the vacuum and the limit
temperature are concerned. The final design has been commited to the firm Hitech
of Catania under the supervision of the group.
4.8. PHOTOMETRIC DATA ACQUISITION AND REDUCTION
4.8
99
Photometric data acquisition and reduction
Supervisor:
Technical Staff:
E. Marilli
V. Greco, C. Lo Presti, P. Massimino
The photometric laboratory deals with:
• The setup and testing of the single channel photometer for the acquisition of photometric data at the focal plane of the 91-cm telescope at Serra La Nave.
• The development of hardware and software for acquisition, reduction and storage of
data.
The large-band photometry with U B V filters and with interferential filters u v b y HW
HN g1 g2 (Stromgren photometric system) is performed by the photon-counting single
channel photometer cooled by a Peltier effect system at about −15◦ C and equipped
with a photometric head characterized by low dark current (about 1cts/sec at −15 ◦ C).
The filters are mounted on the filter wheels operated through a step engine, managed
by the acquisition software OBELIX. The optimization of times to move from one filter
to the next one has been carried out. This system activates two different acquisition
modes: a standard acquisition, which allows observations with one or more filters with
maximum time resolution between two measures of 0.2 s, and a fast acquisition mode with
a maximum time resolution with one filter up to 0.01 s, implemented in the last version
of OBELIX written in Visual Basic (Win Obelix). Besides the photometric acquisition
program OBELIX, two new packages have been implemented in 2002 which allows the
FFT of long time series to seek periodicities. It proved to be very useful in the search for
new pulsating subdwarf, specifically those belonging to the sdB subgroup.
The group goes on maintaining and updating the software ”PHOT” for the data
reduction, which allows the rapid reduction of data in magnitude differential, standard
UBV and Stromgren system. The package runs in DOS and VMS environment. It is
characterized by a high degree of flexibility to adapt to the different requirements of
observation and data reduction.
The group has continued the development a new software which, by using the WEB
and the computing resources accessible via internet, performs:
• automatic cataloguing of acquired photometric data
• photometric archive consultation
• input of new photometric data
• automatic processing of photometric data with display of graphics and tables
4.9
The ”Mario G. Fracastoro” station on Mt. Etna
Supervisor:
Technical staff:
Maintenance staff:
A. Frasca
G. Carbonaro, A. Di Stefano, A. Miccichè, M. Miraglia,
G. Occhipinti, M. G. Puleo
G. Corsaro, C. Scuderi, M. R. Caruso
100
The observing station of Catania Astrophysical Observatory is located at Serra La Nave
(SLN), on Mt. Etna, at an altitude of about 1700 m a.s.l. It has been dedicated to Professor Mario G. Fracastoro, who promoted its building during the period of his directorship
(1954-1967). This site is about 40 km far from Catania and 20 Km from Nicolosi, the
nearest village. Four telescopes are installed in three different domes:
• The 91-cm Cassegrain reflector [figure ]
• The 61/41-cm Schmidt-Cassegrain Universal Telescope [figure]
• The automatic Ritchey-Chretien photometric telescope (APT/1-80cm)
• A 30-cm Cassegrain reflector, hosted in the APT/1-80cm’s building.
The 30-cm telescope is used for educational purposes and outreach activities, e.g., student
training and visitors’ visual observations. Two additional buildings are used as guardian
and guest house, respectively. Moreover, the latter building hosts the mechanical and
electronic laboratories for instrumentation maintenance.
The 91-cm Cassegrain reflector mechanical part was manufactured by Marchiori and
the optics by Tinsley. It has been operating since 1965. The optics have a classic design.
They allow the use of the telescope at its prime focus and at the newtonian focus, with a
relative aperture f/4.68, or in a Cassegrain configuration having a f/15 relative aperture.
The pointing and tracking system, originally operated by the observer and equipped with
fixed frequency engines, has been replaced with brushless engines and digitized reading
of coordinates. A Pentium PC with Asterix 2000 – a software specifically developed by
our technical staff – drives the telescope in semi-automatic mode.
The 91-cm telescope is usually used with the Cassegrain configuration, with the following instruments:
• REOSC Echelle spectrograph (f /15 collimator and CANON camera f=300 mm,
f /2.8) with the possibility of observing in single dispersion (resolution of 0.9 Å/pxl)
or cross dispersion (resolution of 0.15 Å/pxl). The spectrograph is connected to the
telescope by means of an optical fibre and during 2000 it has been equipped with
a polarimetric module for the measurement of the linear and circular polarization,
allowing the determination of the four Stokes parameters. The acquisition system
consists of a CCD camera (1024x1024, with 24 micron pixels), managed by the same
software developed for the TNG cameras.
• Single head photometer for UBV photometry, ubvy-Hγ and cometary bands (IHW).
The photometer can perform photometry with maximum time resolution of 0.1 and
0.5 s, using a single filter or different filters sequentially inserted, respectively.
• Double-channel photometer URSULA for simultaneous UBV photometry of two
near objects.
• Near IR photometer (JHKLM bands) with InSb sensor, cooled by liquid nitrogen,
which is normally used up to K band (2.2 micron).
4.9. THE ”MARIO G. FRACASTORO” STATION ON MT. ETNA
101
• CCD Camera. Some tests have been carried out with the controller developed for
the TNG telescope and a focal reducer with a field of view of about 100 is under
construction as above explained.
The 61/41 cm Universal Schmidt-Cassegrain telescope, built by ”Meccanica Sarti
di Bologna” (1966) is completely manually operated. The Schmidt configuration has a
relative aperture of f /3.5 and a field of view of 4.2 × 4.2 degrees in the photographic
mode. It is equipped with a secondary mirror which allows a quasi-Cassegrain focus, with
a nearly null field of view, used only for photoelectric photometry. The photometer contains standard UBV filters mounted on a rapidly rotating wheel (0.1 Hz), which performs
quasi-simultaneous measurements in the three filters (maximum time resolution of 1 sec)
and is particularly suitable for the study of rapidly evolving events, such as stellar flares.
The telescope is presently being restored in order to implement an automatic control of
the pointing and tracking system, also for objects with large proper motion. It will be
equipped with a CCD camera for the monitoring of Near Earth Orbit (NEO) asteroids in
the framework of the ITANET project.
The APT/1-80cm (Automated Photoelectric Telescope) built by AutoScope Co.
(Tucson AZ, USA) was installed at the end of 1991. The optical configuration is a RitcheyChretien type with absolute aperture of 80 cm and equivalent focal of about 6 m. Both
the telescope and the photometer (UBV) are automatically operated by a PC-AT/386.
The observational efficiency (duty-cycle), over a 10-year operation period, has been estimated to be of about 70%, while the traditional telescopes seldom get 30-40%. The
system is completely automated, including the opening and closing of the sliding roofs of
the rectangular block (4 × 8 m) hosting it. The opening command of the roof is activated
after a meteorological test is passed, on the basis of fixed meteorological limits (absence
of rain, fog, strong wind and so on).
The telescopes of the M.G. Fracastoro stellar station operate for about 350 nights in
a year. Six technicians in turn guarantee the night technical assistance. The 91-cm and
the APT/1-80 cm are fully time allocated, while the 61-cm Schmidt telescope is presently
under revision.
The statistics relative to the use of the telescopes nights/year are listed in the following
table:
Research programs: During 2002 the following research programs have been carried
out at the M. G. Fracastoro station:
• Systematic long-term study of stellar activity by means of wide-band photometry
(APT 80)
• Structure of the chromosphere and its evolution for variable stars belonging to the
RS CVn and T Tauri groups by means of spectroscopic monitoring of the Hα line;
• Correlation between photospheric spots and chromospheric faculae in RS CVn binaries by simultaneous optical photometry and spectroscopy
102
Cassegrain 91-cm
APT/1 80-cm
1999 2000 2001 2002 1999 2000 2001
2002
Nightly use > 50%
167 156 156 161 157 183 100
89
Nightly use < 50%
32
34
38
29
70
38
41
18
a
Maintenance and testing 36
35
26
31
10
6
15
3
b
b
Not used (meteo)
112 115 135
138 117 124 196
199c
Not used (failure)
18
26
10
6
11
15
13
66
Notes: (a) Including the period of inactivity (60 days) spent for the aluminization
of the mirrors and the revision of the bearing of the primary mirror
(b) Including the time spent for the aluminization of the primary mirror (20 g days)
(c) Including 30 nights of inactivity due to the eruption of Mt. Etna
Table 4.1: Telescopes activity
• Measurement of the temperature variation associated with stellar spots
• Characterization of the promary targer of the space mission COROT
• Rotation of young stellar objects (PMS and T Tauri)
• Measurements of chemical abundances and magnetic fields in CP and Ap stars
• Photometric studies of the minor bodies of the Solar System and of the mutual
events of Jupiter’s and Saturn’s satellites
• Partecipation to coordinated multi-site campaign for the observation of Blazars and
ToO
• Mass loss determination in variable star of the P Cygni class
• Spectroscopic studies of planetary nebulae
• Pulsations of sdB stars.
The papers published in internationally referred journal and the invited contribution
totally or partially based on observations made at the M. G. Fracastoro station are: [11],
[12], [15], [18], [20], [26], [28], [30], [33], [34], [35], [36], [38], [39], [42], [46], [56],
[59], [77], [80], [105], [106], [110], [118], [135], [137].
4.10
Solar observation facilities
Supervisors:
Technical staff:
D. Spadaro, F. Zuccarello
S. Billotta (contractor), E. Catinoto, G. Sapienza (until April 1st,
2002), S. Sciuto
Equatorial spar. The equatorial spar (see Fig. 4.3) consists of 6 optical benches, three
of which are devoted to the daily observing program:
4.10. SOLAR OBSERVATION FACILITIES
103
• a bench for the white light observations, sunspot shape and sunspot group drawing;
• a bench for Hα observations, chromosphere and photosphere with Zeiss filter (CCD
camera);
• a bench for Hα visual observations, Halle filter.
Figure 4.3: The equatorial spar.
The data acquired in the framework of this program deal with: groups of sunspots,
faculae, quiescent and active prominences on the disk and at the limb, flares (see Fig. 4.4).
During 2002 the total number of useful observing days has been 305. The standard
sequence of observations consists of:
• one image every 15 min at the center of the Hα line (chromosphere);
• one image every 15 min in the Hα line wing (+5Å, photosphere);
• rapid sequences of images during flares or eruptive prominences.
The works and improvement of services in 2002 include:
• Adjustments and enhancement of performances of the CCD camera (carried out by
the detector laboratory);
• Duplication of the commands to manage telescope control from the room below the
dome (carried out by the staff of the laboratory for telescope automation);
• Installation of a movable lens holder for the focusing and the collimation of various
instruments (provided by the manufacturer TMA);
104
Figure 4.4: An Hα a image of the Sun taken with the Zeiss filter.
• Installation of a second movable lens holder for the focusing and the collimation of
the bench for Hα visual observations, equipped by a Halle filter;
• Installation of a mechanical adjustable support for the Halle filter;
• Installation of a TV camera enabling the remote pointing of the Sun (carried out
by the staff of the laboratory for telescope automation);
• Recording of solar images using the standard international FITS format (carried
out by the staff of the Detector laboratory);
• Implementation of a new procedures for data archiving (carried out by P. Massimino);
• Implementation of IDL routines for a preliminary data analysis.
Catania Observatory makes available solar observations also through its web site. It
shows links to several international research projects and collaborations to which it actively contributes. Notably, owing to the important improvements carried out in 2001 and
2002, on February 26, 2002, Catania Astrophysical Observatory joined the Global HighResolution Hα Network, operated by the Big Bear Solar Observatory (California, USA),
that collects and records chromospheric data obtained by various international observatories, continuously monitoring activity phenomena occurring in the solar chromosphere.
This network aims to provide the solar international community with high quality data
and to carry on specific researches relevant to the study of filaments, prominences and
flares.
4.10. SOLAR OBSERVATION FACILITIES
105
Solar observations carried out in Catania also support the activities of the FrenchItalian solar telescope THEMIS (Tenerife, Canary Islands). Hα full disc images hourly
collected are put on the web page of Catania Observatory, in order to help in the selection
of solar regions to observe by THEMIS (whose instantaneous field of view is smaller than
1 arcmin × 1 arcmin), also taking into account the longitude difference between Canary
Islands and Catania.
106
Chapter 5
Out-reach and Education
Education and public conferences are part of the institutional activities of the Catania
Astrophysical Observatory as science education is a key factor for social development.
The impact of the out-reach programs carried out at Catania Observatory on people, and
especially on the youngest, living in the Catania area and in general in eastern Sicily, has
been improved every year by means of an intense and increasing activity.
Conferences and visits to the Observatory site in Catania (at the “Cittadella Universitaria”) are typical winter time activity. Most of the visits requests come from Sicilian
schools but in many cases schools and various organizations from outside Sicily have come.
After a presentation that could be general or on a particular argument, in case of precise
request, there is the visits to the solar facilities that are in the same building of the observatory and the observation of the Sun. During the more favorable spring and summer
seasons visits are organized also to the “M. G. Fracastoro” observatory mountain station
station. In that case the visit includes a tour to the telescope and observations of the
moon and some of the visible planets, galaxy, nebulae.
5.1
Out-reach Office
Supervisors:
G. Cutispoto, G. Leto
During 2002 the out-reach activity have been largely developed, researchers of OACt
have given their support to the out-reach activity together with Astronomers of the Astrophysics Department of Catania University. Many programs where conducted in coordination with various organizations. As usual we contributed to national events like the
“Settimana della Cultura Scientifica e Tecnologica” organized by Ministero dell’Istruzione,
dell’Universitá e della Ricerca (MIUR), together with local social events like ”La Natura
e la Scienza” organized by Comune di Ragalna (Ct), August 2002.
A special effort has also been done to get funding for this service to the community. The
necessary development of instruments like a dedicated telescope for visual observations
and multimedia projections systems have been partially supported by MIUR/SSPAR.
During 2002 to increase the information on our activity, it has been developed an
out-reach section of the AOCt web site, which includes all necessary information needed
to plan and request visits to the observatory.
107
108
5.1.1
CHAPTER 5. OUT-REACH AND EDUCATION
Public conferences
During 2002 a number of Conferences and courses where solicited to the Out-reach office.
• 19 Febbraio - “Galileo Galilei and the Copernican Revolution” - Liceo Scientifico
Archimede, Acireale - S. Scuderi
• 7 August - ”Scrutare il cielo con le onde ultraviolette” - Ragalna (CT) - I. Pagano
• 13 August - ”L’Universo in Laboratorio” - Ragalna (CT) - G. Strazzulla
• 24 October - ”La mappa celeste tra mitologia e Astronomia” - Rotary Club Acireale
2110o Distretto - E. Marilli
• 31 October - ”La scala delle distanze astronomiche” - Liceo Scientifico ”V. Fardella”,
Trapani - G. Cutispoto
• 22 Novembre - ”Le stelle: formazione ed evoluzione” - Liceo Scientifico ”V. Fardella”,
Trapani - G. Leto
5.1.2
Visits to the Observatory
As every year many schools and various organization requested to be given a conference
and a guided visit to both the “Cittadella Universitaria” site and to the “M. G. Fracastoro”
mountain station. In both cases the visits is split in two parts, the first one is dedicated
to a general introduction to astronomy and astrophysics, the second part is a visit to the
telescope where people have the opportunity to perform observations at the telescope and
ask more questions to the astronomer. In the case of visit to the “Cittadella Universitaria”
site the equatorial spar is used to make live observations of the sun and its active reagions,
while in the case of visits to the “M. G. Fracastoro” mountain station observations of the
Moon and Planets are done by using the facilities available at the 91 cm telescope.
In summer 2002, as usual, the Observatory has organized the opening of telescopes for
citizens. The events has been advertised by local newspapers as “Osservatorio Astrofisico:
visite pubbliche”. The goal of this event is to give singles, families or group of people the
possibility to spent few ours visiting the telescopes site on mount Etna.
Here is the list of the visits, the name of the guiding astronomer is included.
Visits to the Observatory main building at the “Cittadella Universitaria”:
• March 1 - S.M.S. ”D. Alighieri” - Catania - E. Busà
• March 4 - S.M.S. ”G. Verga” - Acicastello (CT) - G. Leto
• March 6 - Liceo Scientifico ”G. Galilei” - Catania - A. Lanza
• March 8 - Liceo Scientifico ”G. Bento” - Vibo Valentia - F.A. Catalano
• March 11 - S.M.S. ”L. Sturzo” - Biancavilla (CT) - M.P. Di Mauro
• March 15 - XV Istit. Compr. ”P. Orsi” - Siracusa - S. Messina
• March 19 - ”Ist. Istr. Secondaria” - Pachino (SR) - G. Catanzaro
5.1. OUT-REACH OFFICE
109
• March 20 - Ist. Istr. Second. ”Megara” - Augusta (SR) - I. Pagano
• March 21 - Ist. Istr. Second. ”Megara” - Augusta (SR) - G. Catanzaro
• March 27 - S.M.S. ”Sacro Cuore di Gesù” - Catania - G. Cutispoto
• April 5 - Liceo Scientifico ”G. Galilei” - Modica (RG) - E. Busà
• April 8 - Liceo Classico ”N. Spedalieri” - Catania - M.P. Di Mauro
• April 10 - Ist. Sup. ”D. Alighieri” - Enna - S. Messina
• April 11 - Ist. Istr. Sup. ”M. Amari” - Linguaglossa (CT) - F.A. Catalano
• April 15 - Ist. Magistrale ”V. Capialbi” - Vibo Valentia - A. Lanza
• April 17 - Ist. Sup. ”Leonardo da Vinci” - Catania - G. Leto
• April 19 - Ist. Isr. Sec. ”A. Cascino” - Piazza Armerina (EN) - I. Pagano
• April 19 - Liceo Scientifico ”V. Romano” - Piazza Armerina (EN) - I. Pagano
• April 24 - Ist. Compr. ”E. Fermi” - S.G. la Punta (CT) - M.P. Di Mauro
• April 26 - Ist. Sup. ”Alaimo da Lentini” - Lentini (SR) - G. Catanzaro
• April 29 - 2nd Ist. Compr. ”C. Sgroi” - Pachino (SR) - G. Cutispoto
• May 6 - Ist. Compr. ”S. Scandurra” - Aci S. Filippo (CT) - G. Catanzaro
• May 8 - Ist. Super. ”Gorgia” - Lentini (SR) - A. Frasca
• May 13 - Ist. Istr. Sec. ”F. Fedele” - Agira (EN) - G. Leto
• May 15 - Circolo Didattico ”P.A. Coppola” - Catania - M.E. Palumbo
• May 17 - Liceo Scientifico ”G. Galilei” - Catania - E. Busà
• May 20 - Liceo Classico ”T. Gargallo” - Siracusa - M. Ternullo
• May 21 - Ist. Tec. Comm. ”De Felice” - Catania - S. Messina
• May 22 - Ist. Sup. ”N. Pizi” - Palmi (RC) - A. Lanza
• May 23 - Ist. Sup. ”Orsoline” - Siracusa - G. Catanzaro
• May 24 - Ist. Prof. Stat. Alberghiero - Catania - S. Messina
• May 29 - S.M.S. ”Don Dilani” - Paternò (CT) - G. Cutispoto
• May 31 - Ist. Com. ”Leonardo da Vinci” - Misterbianco (CT) - R. Ventura
• July 9 - Comunità ”Ausilia” - Pedara (CT) - R. Ventura
Visits to the Observatory telescopes at the “M. G. Fracastoro” mountain
station, Etna (Ragalna, Ct):
110
• March 19 - Ist. Istr. Secondaria - Pachino - G. Cutispoto
• March 20 - Ist. Istr. Second. ”Megara” - Augusta (SR) - A. Frasca
• April 8 - Liceo Classico ”N. Spedalieri” - Catania - G. Cutispoto
• April 9 - Liceo Ginnasio Statale ”G. Verga” - Adrano (CT) - G. Cutispoto
• April 10 - Ist. Sup. ”D. Alighieri” - Enna - A. Frasca
• April 11 - Ist. Istr. Sup. ”M. Amari” - Linguaglossa (CT) - E. Marilli
• April 17 - Ist. Sup. ”Leonardo da Vinci” - Catania - S. Messina
• April 19 - Ist. Isr. Sec. ”A. Cascino” - Piazza Armerina (EN) - I. Pagano
• April 19 - Liceo Scientifico ”Romano” - Piazza Armerina (EN) - I. Pagano
• May 6 - Liceo Scientifico ”E. Majorana” - S.G. la Punta (CT) - G. Catanzaro
• May 7 - Liceo Scientifico ”E. Medi” - Barcellona P.G. (ME) - A. Lanzafame
• May 13 - Ist. Istr. Sec. ”F. Fedele” - Agira (EN) - G. Cutispoto
• May 16 - Liceo Classico ”F.li Testa” - Nicosia (EN) - S. Messina
• May 17 - Liceo Scientifico ”G. Galilei” - Catania - S. Scuderi
• May 20 - Liceo Classico ”T. Gargallo” - Siracusa - S. Scuderi
• May 21 - Studenti c.d.l. Matematica Univ. di Catania - C. Blanco
• June 17 - Visita pubblica - G. Cutispoto
• June 18 - Visita pubblica - G. Cutispoto
• June 19 - Visita pubblica - S. Messina
• 14 July - Circolo Didattico ”S. Giuffrida” - G. Cutispoto
• July 15 - Club Alpino Italiano Sez. Belpasso (CT) - S. Scuderi
• July 16 - Visita pubblica - G. Cutispoto
• July 17 - Visita pubblica - S. Scuderi
• July 18 - Associazione Nazionale Forense - Catania - G. Catanzaro
• July 20 - Rotary Club, 2110o Distretto - Lentini - E. Marilli
• July 27 - Comune Aci S. Antonio (ass. Servizi Sociali) - G. Leto
• July 28 - Visita pubblica - S. Messina
• July 29 - Visita pubblica - G. Cutispoto
5.1. OUT-REACH OFFICE
111
• July 30 - Comune Aci S. Antonio (ass. Servizi Sociali) - G. Leto
• August 2 - Comune Aci S. Antonio (ass. Servizi Sociali) - I. Pagano
• August 11 - ITT-NAS Sigonella - G. Leto
• August 12 - UGAF (Ass. Seniores Aziende FIAT) - G. Cutispoto
• August 13 - Visita pubblica - G. Cutispoto
• August 25 - Visita pubblica - S. Messina
• August 26 - Visita pubblica - G. Cutispoto
• August 27 - Visita Pubblica - G. Cutispoto
• September 12 - FIDAS (Gruppo donatori sangue) - Paternò (CT) - S. Messina
• September 13 - Visita pubblica - G. Catanzaro
• Setembre 14 - Visita pubblica - A. Lanza
• September 27 - ALATEL (Ass. Lavoratori Anziani Telecom) - G. Cutispoto
• October 10 - Istituto Comprensivo ”D. Alighieri” - Nicosia (EN) - S. Messina
• October 11 - I.T.C. ”G. De Felice” - Catania - G. Catanzaro
• October 14 - Istituto Paritario ”Maria Ausiliatrice” - Catania - G. Cutispoto
• October 14 - Istituto Comprensivo ”D. Alighieri” - Nicosia (EN) - G. Cutispoto
• October 21 - Liceo Scientifico ”Leonardo” - Giarre (CT) - G. Cutispoto
• October 25 - S.M.S. ”S. Quasimodo” - Catania - A. Lanza • October 26 - Liceo Scientifico ”G. Seguenza” - Messina - G. Cutispoto
5.1.3
Special events
On August 10th 2002 a special event was organized (”Perseides 2002”), in order to give
citizen the opportunity to learn more about meteor showers. During the first part of the
night the M. G. Fracastoro Mountain Station was available for the public. The organized
visits included a 30 minutes outdoor conference with the projection of a multimedia
presentation and a permanence in predefined places close to the telescopes domes for the
direct observation of the meteor shower. About 400 people where split in groups guided
by G. Cutispoto, G. Leto, and I. Pagano.
112
5.2
Advanced course on detector technology
During 2002 COLD researchers have given a series of lectures attended by members of
the research staff of LABEN SpA (a firm of the Finmeccanica group). The subject of
the lectures was the CCD detector starting from the basic principles up to the most advanced topics. The front-end electronics and the measurements of its main characteristics
were also covered. The theoretical lectures were followed by laboratory activity at our
characterization facility.
5.3
University Courses and high level Educational
Activity
During 2002 a number of courses and lectures have been given by OACt researchers:
• “Risultati recenti della Cosmologia”, Corso di agg.to per docenti scuole superiori
aderenti all’ANSLIN, V. Antonuccio
• “Corso di Cosmologia post-ricombinazione”, per il XVII Ciclo del Dottorato di
ricerca in Fisica (Univ. Ct, 40 ore), V. Antonuccio
• “CCD detector: basic principles, the front-end electronics, measurements”, personnel of LABEN SpA (a firm of the Finmeccanica group), M. Belluso, G. Bonanno.
The theoretical lectures were followed by laboratory activity at our characterization
facility.
• “Renormalization group and its applications in Physics and Astrophysics”, University of Naples, A. Bonanno
• “Fondamenti di Informatica”, Corso di Laurea in Chimica Industriale, 1o anno, U.
Becciani
• “Informatica”, Corso di Laurea in chimica, U. Becciani
• “Corso Fisica Computazionale”, Dottorato di Ricerca XVII ciclo, U. Becciani
• Lectures on “Introduction to physics of supernovae” in the framework of the course
on “Peculiar astrophysical environments” for PhD students in physics at the Catania
University (XVI and XVII cycles of PhD courses), V. Costa.
• Lecture on “Thomson diffusion, Compton effect and inverse Compton effect” in
the framework of the Radioastronomy course for the IV year students in physics,
Catania University, V. Costa.
• “CCD detectors characterization”, Physics course of the Department of Physics and
Astronomy, Catania University, S. Scuderi
• “Ion irradiation of astrophysical relevant materials”, Physics course of the Department of Physics and Astronomy, Catania University, G.A. Baratta, M.E. Palumbo,
the course includes lectures (6 hours) plus laboratory practice (9 hours)
5.4. PH.D. STUDENTS
113
• “Introduction to Astronomy - Basics of photometry and Spectroscopy”, one week
stage at M.G. Fracastoro station for students of Scuola Superiore di Catania, S.
Catalano, A. Frasca
5.4
Ph.D. Students
Ph.D. students working at Catania Astrophysical Observatory during 2002 were:
- Biazzo Katia: “Precise photospheric temperature measurements from line-depth
ratios”
- Bentivegna Eloisa: “Cosmological perturbations from the Planck era and renormalization group equations for quantum gravity”
- Contarino Lidia: “Magnetic reconnection in the low solar atmosphere related to a
filament eruption”
- Di Giorgio Salvatore: “Studio di archi coronali solari in UV estremo, su dati del
Coronal Diagnostic Spectrometer (CDS) di SOHO”
- Ferro Daniela: “Modelli N-Body e tools di visualizzazione e di analisi“
- Murabito Anna Lisa: “Metodi di inversione dei dati eleiosismici per lo studio della
struttura e dinamica del Sole”
- Leccia Silvio: “Asteroseismology of solar-type stars: results from high-resolution
spectroscopy”
- Palazzo Melissa: “Il ruolo della viscositá nella formazione dei jets nei dischi di
accrescimento”
- Romano Paolo: ”The role played by the helicoidal structure on the eruption of
filaments”
- Romeo Alessio: “The Evolution of the X-ray luminosoty funcion of galaxy Clusters”
114
Chapter 6
Staff members
During 2002 the selection process for a “Categoria D1” administrative staff position was
completed. However, it was not possible to appoint the new employee because the stop to
new enrollments posed by the “Legge Finanziaria 2002” law. Since one “D3” permanent
staff member retired during 2002, a request to INAF has been sent to cover the position
with a ”C1” unit under the criterion of “mobilità”. All the necessary steps have been done
to this purpose, and the transfer of the unit is waiting for the final institutional consent.
A selection for three positions of ”Astronomo Associato” has been also completed. Dr.s
A.F. Lanza, A. Magazzù, and D. Spadaro were selected and their enrollment has been
approved by the “Direttivo INAF” on November 19 2002. However, the hiring is not
effective yet, because the stop to new enrollments posed by the “Legge Finanziaria 2002”
law.
6.1
Staff on 31 December 2002
ASTRONOMI
Ordinari
Bonanno G., Catalano S., Strazzulla G.
Associati
Baratta G., Cutispoto G., Marilli E.
Ricercatori
Antonuccio V., Becciani U., Bonanno A., Busà I., Catanzaro G., Cosentino R., Di Mauro
M. G., Frasca A., Lanza A. F., Lanzafame G., Leone F., Leto G., Magazzù A., Messina
S., Pagano I., Palumbo M.E., Scuderi S., Spadaro D., Ternullo M., Ventura R.
AREA AMMINISTRATIVO-CONTABILE
Categoria EP3
Del Popolo S., Rapisarda M.L.
115
116
CHAPTER 6. STAFF MEMBERS
Categoria C5
Mellini M., Tringale G.
Categoria C2
Scafili M.
Categoria C1
Costa P., Romania V.
AREA DELLE BIBLIOTECHE
Categoria D3
Mangano A.
Categoria C3
Domina D., Recupero D., Santagati L.
AREA TECNICA ed ELABORAZIONE DATI
Categoria EP3
Massimino P. (ind elab dati)
Categoria EP2
Sardone S. (ind. ottico-meccanico), Spinella F. (ind. elettronico)
Categoria EP1
Presti C. (ind. elab. dati)
Categoria D3
Caripoli G., Catinoto E., Di Benedetto R., Sciuto S.
Categoria D1
Belluso M., Costa A.
Categoria C5
Bruno P. (elab. dati), Greco V., Martinetti E.
Categoria C3
Calı̀ A., Carbonaro G., Gentile G., Lampò R., Miraglia M., Wanausek A.
Categoria C2
Bellassai M. (uff. tecnico)
6.1. STAFF ON 31 DECEMBER 2002
117
Categoria C1
Occhipinti G., Miccichè A.
AREA DEI SERVIZI GENERALI, AUSILIARI E TECNICI
Categoria B4
Puleo M. G., (ind. mecc.)
Categoria B3
Calı̀ M., Castorina G., Distefano A. (ind. mecc.), Giuffrida A. (ind. elab. dati), Saccone R. (ind. amm.), Timpanaro M.C. (ind. elettronico)
Categoria B2
Corsaro G., Santocono O., Scuderi C., Ventimiglia A., Zingale G.
Categoria B1
Caruso M. R.
118
CHAPTER 6. STAFF MEMBERS
List of Publications 2002
7.1
Papers on refereed Journals
[1] Antonuccio-Delogu V., Becciani U., van Kampen E., Pagliaro A., Colafrancesco S., Germaná A., Gambera M.: Properties of galaxy haloes in clusters
and voids, Monthly Notices of the Royal Astronomical Society, v. 332, Issue 1, p.
7-20, 2002
[2] Baratta G.A., Leto G., Palumbo M.E.: A comparison of ion irradiation and
UV photolysis of CH4 and CH3OH, Astronomy & Astrophysics, 384, p. 343-349,
2002
[3] Belvedere, G., Lanzafame G.: SPH Simulations of Spiral Shocks in Discs around
Black Holes, Publications of the Astronomical Society of Japan, Vol.54, No.5, p.781785, 2002
[4] Bernacca P.L., Antonello E., Preite Martinez A., Bertola F., Catalano S., Rodonò
M, ..., Scuderi S., ..., Bonanno G., .., Lanzafame A., Pagano I., et al., :Ultraviolet Astronomy from the Space Station: A Case Study. Research Signpost, p.
??
[5] Bonanno A., Reuter M.: Cosmology with self-adjusting vacuum energy density
from a renormalization group fixed point, Physics Letters B, v.527, p.9-17, 2002
[6] Bonanno A., Reuter M.: Cosmology of the Planck era from a renormalization
group for quantum gravity, Physical Review D 65, Issue 4, id. 043508, 2002
[7] Bonanno A., Schlattl H., Paternò L.: The age of the Sun and the relativistic
corrections in the EOS, Astronomy & Astrophysics vol.390, p.1115-1118, 2002
[8] Bonanno A., Elstner D., Rüdiger G., Belvedere G.: Parity properties of an
advection-dominated solar a2 O dynamo, Astronomy & Astrophysics vol.390, p.673680, 2002
[9] Cassaro P., Stanghellini C., Dallacasa D., Bondi M., Zappalà, R. A.: Bendings of
radio jets in BL Lacertae objects. I. EVN and MERLIN observations, Astronomy
and Astrophysics, vol.381, p.378-388 , 2002
[10] Cataldo F., Baratta G.A., Strazzulla G.: HE+ ion bombardment of C60
fullerene: an FT-IR and raman study, Fullerenes Nanotubes and Carbon Nanostructures, vol 10, n.3 p. 197-206, 2002
119
120
LIST OF PUBLICATIONS 2002
[11] Catalano S., Biazzo K., Frasca A., Marilli E.: Measuring starspot temperature
from line depth ratios: I. The method, Astronomy & Astrophysics vol.394, p.10091021, 2002
[12] Catanzaro G., Leone F.: On the behavior of the CII 4267.261, 6578.052 and
6582.882 Ålines in chemically peculiar and standard stars, New Astronomy, Vol.7,
Issue 8, p. 495-510, 2002
[13] Cutispoto G., Pastori L., Pasquini L., de Medeiros J.R., Tagliaferri G., Andersen
J.: Fast-rotating nearby solar-type stars I. Spectral classification, Li abundances, v
sin i and X-ray luminosities, Astronomy & Astrophysics vol.384, p.491-503, 2002
[14] Di Mauro M.P., Christensen-Dalsgaard J., Rabello-Soares M.C., Basu S.: Inferences on the solar envelope with high-degree modes, Astronomy & Astrophysics
vol.384, p.666-677, 2002
[15] Frasca A., Çakirli Ö., Catalano S., Ibanoglu C., Marilli E., Evren S. and Tas
G.: H-alpha spectroscopy and BV photometry of RT Lacertae, Astronomy & Astrophysics vol.388, p.298-308, 2002
[16] Lamers H.J.G.L.M., Panagia N., Scuderi S., Romaniello M., Spaans M., De Wit
W.J., Kirshner R.: Ongoing massive stars formation in the bulge of M51, The
Astrophysical Journal, 566, p. 818-832, 2002
[17] Lanza A.F., Rodonò M.: Asteroseismic tests for models of magnetically active
close binaries with orbital period modulation, Astronomy & Astrophysics vol.390,
p.167-172, 2002
[18] Lanza A.F., Catalano S., Rodonò M., Ibanoglu C., Evren S., Tas, G., Çaakirli Ö,
Devlen A.: Long-term starspot evolution, activity cycle and orbital period variation
of RT Lacertae, Astronomy & Astrophysics, vol.. 386, p.583-605, 2002
[19] Lanzafame A.C., Brooks D.H., Lang J., Summers H.P., Thomas R.J., Thompson
A.M.: ADAS analysis of the differential emission measure structure of the inner
solar corona. Application of the Data Adaptive Smoothing approach to the SERTS89 active region spectrum, Astronomy & Astrophysics vol.384, p.242-272, 2002
[20] Messina S., Guinan E.F.: Magnetic activity of six young solar analogues. I Starspot
cycles from long-term photometry, Astronomy & Astrophysics vol.393, p.225-237,
2002
[21] Michels J. G., Raymond J. C., Bertaux J. L., Quémerais E., Lallement R., Ko Y.K., Spadaro D., Gardner L.D., Giordano S., O’Neal R., Fineschi, S., Kohl J.L.,
Benna C., Ciaravella A., Romoli, M., Judge D.: The Helium Focusing Cone of the
Local Interstellar Medium Close to the Sun, The Astrophysical Journal, Vol. 568,
Issue 1, p. 385-395, 2002
[22] Paternò L., Belvedere G., Kuzanyan K.M., Lanza A.F.: Asymptotic dynamos in
late-type stars, Mon. Not. R. Astron. Soc. vol. 336, Issue 1, p. 291-298, 2002
7.1. PAPERS ON REFEREED JOURNALS
121
[23] Romaniello M., Panagia N., Scuderi S., Kirshner R.P.: Accurate stellar population
studies from multiband photometric observations, The Astronomical Journal 123,
p. 915-940, 2002
[24] Rüdiger G., Elstner D., Lanza A.F., Granzer Th.: Orbital period modulation in
close binaries due to cyclic a2- dynamo activity, Astronomy & Astrophysics, vol.392,
p.605-611, 2002
[25] Strazzulla G., Baratta G.A., Domingo M., Satorre M.A.: Ion irradiation of
frozen C2Hn (n=2, 4, 6), Nucl. Instr. Meth. B 191, 714-717, 2002
[26] Umana G., Leone F., Trigilio C.: The origin of the radio emission from beta Lyrae,
Astronomy and Astrophysics, vol.391, p.609-615, 2002
[27] Ventura R., Spadaro D., Uzzo M., Suleiman R.: Erratum:UV line intensities and
flow velocity distribution in two coronal mass ejection as deduced by UVCS-SOHO
observations, Astronomy & Astrophysics,vol.395, p.975, 2002
[28] Villata M., ... , Frasca A., Marilli E. ,..., Catalano S., ... ,Uemura M.: The
WEBT BL LAC campaign 2000, Astronomy & Astrophysics vol. 390, p.407-421,
2002
[29] Zaqarashvili T., Javakhishvili G., Belvedere G.: On a Mechanism for Enhancing
Magnetic Activity in Tidally Interacting Binaries, Astrophysical Journal, Vol. 579,
Issue 2, p. 810-816, 2002
7.1.1
In press
[30] Alonso M.S., Lopez-Garcia Z., Malaroda S., Leone F : Element abundance studies
of CP stars. The helium-weak stars HD19400, HD34797, HD35456, Astronomy and
Astrophysics, in press
[31] V. Antonuccio, U. Becciani, D. Ferro, Comp. Phys. Com., Comp. Phys. Comms.
2002, in press
[32] Baratta G.A., Domingo M., Ferini G., Leto G., Palumbo M.E., Satorre M.A.,
Strazzulla G.: Ion irradiation of CH4 containing icy mixtures, Nucl. Instr. Meth.
B, in press
[33] Blanco C., Cigna M., Riccioli D.: Photoelectric observations of asteroids: rotational
period, lightcurves, shape and spin Astronomy & Astrophysics axis determination,
Annales de Physique, in press
[34] Blanco C., Cigna M., Riccioli D.: Rotational periods of asteroids.III, Planetary and
space science, in press
[35] Bonanno A., Catalano S., Frasca A., Mignemi G., Paternò L.: PG 1613+426:
a new sdB pulsator, Astronomy & Astrophysics, in press
[36] Çakirli Ö., Ibanoglu C.,Frasca A., Catalano S.: H-alpha variations of the RS
CVn type binary ER Vulpeculae, Astronomy & Astrophysics, in press
122
[37] Catanzaro G., L. Bianchi L., Scuderi S., Manchado A. Spectroscopy of early-type
star candidates in M33 and NGC6822. II Astronomy & Astrophysics, in press
[38] Catanzaro G., Leone F.: Variability of the HeI5876 A line in early type Chemically peculiar stars. Paper II, Astronomische Nachrichten in press
[39] Cutispoto G., Messina S., Rodonò M.: Long-term monitoring of active stars.X.
Photometry collected in 1994, Astronomy & Astrophysics in press
[40] Cutispoto G., Tagliaferri G., de Medeiros J.R., Pastori L., Pasquini L., Andersen J.: Fast-rotating nearby solar-type stars II. Li abundances, v sin i and X-ray
luminosities relationships, Astronomy & Astrophysics, in press
[41] Di Mauro M. P., Christensen-Dalsgaard J., Kjeldsen H., Bedding T., Paterno’ L.:
Convective overshooting in the evolution and seismology of eta Bootis, Astronomy
& Astrophysics, in press
[42] Garcia-Alvarez D., Foing B.H., Montes D., Oliveira J.M., Doyle J.D.,Messina S.,
Lanza A.F., Rodonò M., ... et al.: Simultaneous optical and X-ray observations of
flares and rotational modulations on the RS CVn binary HR 1099 (V711 Tau) from
the MUSICOS campaign, Astronomy & Astrophysics, in press
[43] Lanzafame G.: Spirals and shock fronts developed around accretion discs in line
close binaries: physically viscous and non viscous SPH modelling , Astronomy &
[44] Leto G., Baratta G.A.: Ly-α, photon induced amorphization of IC water ice
at 16 kelvin effect and quantitative comparison with ion irradiation, Astronomy &
[45] S. Covino, et. al. including Magazzú A.: Optical and NIR Observations of the
Afterglow of GRB 020813, Astronomy & Astrophysics, in press
[46] Massaro E., Giommi P., Perri M., Tagliaferri G., Nesci R., Tosti G., Ciprini S., Maesano M., Montagni F., Ravasio M., Ghisellini G.,Frasca A., Marilli E., Valentini
G., Kurtanidze O. M., Nikolashvili M.: Optical and X-ray observations of the two
BL Lac objects OJ 287 and MS 1458+22, Astronomy & Astrophysics, in press
[47] Palumbo M.E., Strazzulla G.: Nitrogen condensation on water ice, Canadian
Journal of Physics, in press
[48] Romano P., Contarino L., Zuccarello F.: Eruption of a helically twisted prominence,
Solar Physics, in press
[49] Spadaro D., Lanza A.F., Lanzafame A.C., Karpen J.T., Antiochos S.K., Klimchuk J.A., MacNeice P.J.: A transient heating model for coronal structure and
dynamics, The Astrophysical Journal, in press
[50] Stift M. J.,Leone F. : Magnetic intensification of spectral lines Astronomy and
[51] Zuccarello F., Contarino L., Romano P., Priest E.R.: Flare activity in solar active
region 8421 observed by TRACE satellite, Astronomy & Astrophysics, in press
7.2. INVITED TALKS
7.2
123
Invited talks
[52] Antonuccio V., Becciani U., Romeo A.:Simulazioni cosmologiche: vuoti,
ammassi di galassie e gas primordiale, Capri 2002, Cilea - Invited Talk
HTTP://WWW.CILEA.IT/CONVEGNI/ARCHIVIOCONVEGNI.HTM
[53] Antonuccio V., Becciani U.,Romeo A.:Simulazioni cosmologiche: vuoti,
ammassi di galassie e gas primordiale, Capri 2002, Cilea - Invited Talk
[54] Becciani U., Antonuccio V., Ferro D.: FLY: un codice N-Body per MPP, tecniche di visualizzazione e distribuzione del calcolo, Capri 2002, Cilea - Invited Talk
[55] Barstow M. A., Ribak E. N., Brosch N., Cheng F-Z., Dennefeld M., Gomez de
Castro A. I., van der Hucht K. A., Kappelmann N., Moisheevh A., Pagano I.,
Sahade J., Shustov B., Wamsteker, W.,Werner, K., Invited talk, The WSO, a worldclass observatory for the ultraviolet”, Eds J. C. Blades, Oswald H. Siegmund, SPIE
4854-88 2002
[56] Catalano S., Biazzo K., Frasca A., Marilli E., Messina S., Rodonò M.: Temperature and size of starspots from line depth ratios, Astronomische Nachrichten
vol.323, 260-264, 2002
[57] Cutispoto G.: Li (and other light elements) and stellar activity, Astronomische
Nachrichten vol.323, p.325-328, 2002
[58] Di Mauro M.P., Christensen-Dalsgaard J., Pijpers F., Hao J.: An Attempt at
Mode Identification for V480 Tau , Radial and Nonradial Pulsations as Probes
of Stellar Physics, ASP Conference Proceedings, Vol. 259. Edited by Conny Aerts,
Timothy R. Bedding, and Jörgen Christensen-Dalsgaard. Also IAU Colloquium 185.
San Francisco: Astronomical Society of the Pacific, p.336, 2002
[59] Lanza A.F., Rodonò M.: Gravitational quadrupole-moment variations in active
binaries, Astronomische Nachrichten vol.323, p. 424-431,2002
7.2.1
In press
[60] Bonanno A., Elstner D., Belvedere G., Rüdiger G.:Advection-dominated positive
alpha dynamo in the solar convective shell, Proc. IAGA-IASPEI Joint Scientific
Assembly, Hanoi,19-31 August 2001, IAGA Session G7.04, (2002) (RELAZIONE
SU INVITO), in press
[61] Paternó L., Di Mauro M.P., Ventura R.: From helio- to astero-seismology, a new
challenge for understanding stellar evolution, in Recent Reasearch Developments in
Astronomy & Astrophysics, Research SignPost Publ., India, in press.
124
7.3
Contributed papers to international meetings
[62] Blanco C.: Results of the observational campaigns on asteroids made at Catania,
Planetary Science fourth Italian Meeting held in Bormio, Italy, Jan. 20-26, 2002 ,
A. Manara and E. Dotto (Eds), p.13, 2002
[63] Cassaro P., Zappalà R.A., Belvedere G., Palazzo G., Lanzafame G., Costa V.:
Simulazioni numeriche di dischi di accrescimenteo attorno a buchi neri: possibile
connessione HBL-LBL. Proc of LXXXVIII Congresso Nazionale Società Italiana di
Fisica, Alghero, 26 sett. 1 ott. 2002 p. 12
[64] Catalano, S., Marino, G., Frasca, A., Marilli, E., Messina, S., Cutispoto, G., Rodonò,
M.: Spots and Plages on HK Lac Poster Paper at the 1st Potsdam Thinkshop on
Sunspots and Starspots, eds. K. Strassmeier & A. Washuettl, AIP, p. 47-50, 2002
[65] Contarino L., Romano P., Ternullo M., Zuccarello F.: Characteristics of sunspotgroups hosting M and X flares, Poster Proceedings of the ”First Potsdam Thinkshop
on Sunspots and Starspots” May, 6-10 2002, K.G Strassmeier and A. Washuettl
(Eds), AIP, p.33-35, 2002
[66] Contarino L., Romano P., Zuccarello F., Yurchyshyn V.B.: Optical and EUV observation of a filament destabilization and pre-eruption reconnection, Proc. of ”Solar
variability: from core to outer frontier”, ESA SP 506, 573-576
[67] Di Mauro M.P., Christensen-Dalsgaard J.: Helioseismic investigation of the solar
envelope, in ”Solar Variability: From core to outer frontiers”10th European Solar Physics Meeting Praha , September 9-14, 2002,Czech Republic, EPD Special
Publication SP-506 , ed. by A. Wilson, 879-882, 2002
[68] Gratton R., Bonanno G., Brocato E., Carretta E., Claudi R., Cosentino R.,
Desidera S., Dolci M., Endl M., Lucatello S., Marzari F.,Scuderi S.: SARG Extra
Solar Planet Search, Proceedings of the First Eddington Workshop on Stellar Structure and Habitable Planet Finding, 11 - 15 June 2001, Cordoba, Spain. Editor: B.
Battrick, Scientific editors: F. Favata, I. W. Roxburgh & D. Galadi. ESA SP-485,
p. 265 - 268, 2002
[69] Grundy W. M., Levison H. F., Parker J. W., Allen R. L., Ball L. C., Cooper J. F.,
de Sanctis M. C., Farnham T. L., Gladman B., Hahn J. M., Hergenrother C. W.,
Kavelaars J. J., Krueger H., Lien D.J., Malhotra R., Mastrapa R. M. E., Quillen A.,
Srama R., Stansberry J. A.,Strazzulla G., Terrile R. J., Trujillo C. A.: Probing
The Solar System’s Outermost Frontier: The Future of Kuiper Belt Studies, ASP
Conference Proceedings, Vol. 272. Edited by Mark V. Sykes p. 337-354, 2002
[70] Hernanz M., González-Riestra R., Wamsteker W., Shustov B., Barstow M., Brosch
N., Fu-Zhen, C., Dennefeld M., Dopita M., Gómez de Castro A.I., Kappelmann
N.,Pagano I., Sahade, J., Haubold H., Solheim J.-E., Martı́nez P.: WSO/UV:
World Space Observatory/Ultraviolet Classical Nova Explosions, in International
Conference on Classical Nova Explosions. AIP Conference Proceedings, Vol. 637.
Sitges, Spain, 20-24 May, 2002. Edited by Margarita Hernanz and Jordi José. American Institute of Physics, 2002, p.238-241, 2002
7.3. CONTRIBUTED PAPERS TO INTERNATIONAL MEETINGS
125
[71] Lanza A. F., Rodonò M., Pagano I.: Preliminary attempts to discriminate
stellar activity phenomena and planetary transits, oral presentation at the Exoplanet Working Group Meeting during the Second Corot Week, Paris-Meudon,
A. Baglin, P. Barge, C. Catala, W. Weiss (Eds.), HTTP://WWW.ASTRSPMRS.FR/PROJETS/COROT/MEETING/CW2.HTML
[72] Lanzafame A.C., Busà I., Rodonò M.: Chromospheric two-component NLTE modelling of RS CVn systems, Modelling of Stellar Atmospheres IAU Symposium
[73] Lanzafame G., Costa V., Zappalà R.A. Belvedere G.: A chemical evolution
approach to the study of accretion disks via a Lagrangian SPH code, Proc of
LXXXVIII Congresso Nazionale Società Italiana di Fisica, Alghero, 26 sett. 1 ott.
2002 p. 13
[74] Leto G., Baratta G.A.: Laboratory studies of Lyman-alpha photon irradiation
of crystalline water ice, European Geophysical society, Nice, April 2002, EGS02-A01249;PS8-1TH3A-002
[75] Linsky J. L.,Pagano I., Valenti J., Gagné M., Duncan D. K.:HST/STIS High
Resolution Echelle Spectra of α Centauri A (G2 V), American Astronomical
Society Meeting 201, #12.09
[76] Pagano I., Lanza A.F., Rodonò M., Barge P., Llebaria A.: Modelling
the rotational modulation of the Sun as a star: a method to enhance the
detection of planetary transit signals in the presence of stellar activity,
oral presentation at the COROT Week N.3, Liege, electronic publication on
HTTP://WWW.ASTRO.ULG.AC.BE/ORIENTATION/ASTEROSIS/WEEK3/TEXTE/EWGPAGANO.PDF
[77] Pagano I., Busà I., Catalano S., Cutispoto G., Frasca A.,
Lanza A.F., Marilli E., Messina S., Rodonò M.: Flare, microflares
and rotational modulation in late dwarfs and RS CVn system, oral presentation at the COROT Week N.3, Liege, electronic publication on
http://www.astro.ulg.ac.be/orientation/asterosis/week3/texte/apwgpagano.PDF
[78] Pagano I.: Fundamental Science program definition: a contribution from
the Italian NWWG, oral presentation at the WSO/UV Implementation
Committee Meeting, Moscow 19-23 May 2002, electronic publication on
HTTP://WSO.VILSPA.ESA.ES/CONFERENCES/MOSCOW 2002/IV/MOSCOWIP.PPT
[79] Pallavicini R., Zerbi, F., Beuzit, Jean-Luc, Bonanno, G. Catalano S., .... et
al: Scientific Objectives and Design Study of an Adaptive Optics Visual Echelle
Spectrograph and Imager Coronograph (AVES-IMCO) for the NAOS Visitor Focus
at the VLT, Proc. of the ESO workshop held in Garching, Germany 11-15 June
2001, p. 205, 2002
[80] Raiteri C.M., ... ,Frasca A., Marilli E., ... ,Catalano S., ... and D’Alessio F.:
The Whole Earth Blazar Telescope and the BL Lac Campaign 2000, Proceedings
of the international workshop ”Blazar Astrophysics with Beppo SAX and Other
Observatories” ASI SP -2002, p.219-224, 2002
126
[81] Romaniello M., Panagia N.,Scuderi S., Gilmozzi R., Tolstoy E., Favata F., Kirshner R.P., T Tauri Stars in the Large Magellanic Cloud: A Combined HST and
VLT Effort, 2002, in proceedings of the ESO Workshop on The Origins of Stars and
Planets: The VLT View, 24-27 April 2001, Garching, Germany, p. 275.
[82] Romano P., Contarino L., Zuccarello F.: Development of a filament eruption during
a solar flare, Proc. of ”Magnetic coupling of the solar atmosphere - SOLMAG” ESA
SP-505, p.553-556, 2002
[83] Romano P., Contarino L., Zuccarello F.: Changes in magnetic field topology and
current intensity during a filament eruption, Proc. of ”Solar variability: from core
to outer frontiers ” ESA SP. 506, 733-736
[84] Spadaro D.: Space observations of the solar atmosphere: recent results and
prospects, Proceedings of the session G6.01 ”History of Geomagnetism, Aeronomy and Space Physics”, 9th Scientific Assembly of IAGA (Hanoi, 2001), ed. W.
SchroEder, Science Edition, Bremen, p. 7, 2002.
[85] Spadaro D., Lanza A.F., Lanzafame A.C., Karpen J.T., Antiochos S.K., Klimchuk J.A., MacNeice P.J.: Hydrodynamic models of transiently heated solar coronal loops, Magnetic Coupling of the Solar Atmosphere” (Santorini, 2002), ed. H.
Sawaya-Lacoste, ESA SP-505, 583-586, 2002.
[86] Spadaro D., Lanza A. F., Lanzafame A. C., Karpen J. T., MacNeice P.J., Antiochos S. K., Klimchuk, J. A.: Hydrodynamic simulations of coronal loops subject to
transient heating, In Proceedings of the SOHO 11 Symposium on From Solar Min
to Max: Half a Solar Cycle with SOHO, 11-15 March 2002, Davos, Switzerland.
A symposium dedicated to Roger M. Bonnet. Edited by A. Wilson, ESA SP-508,
Noordwijk: ESA Publications Division, ISBN 92-9092-818-2, 2002, p. 331 - 334,
2002
[87] Strazzulla G., Dotto E., Barucci M. A., Blanco A., Orofino V.: Space Weathering
Effects on Small Body Surfaces: Laboratory Fast Ions Bombardment, American
Astronomical Society, DPS meeting #34, #14.02
[88] Ternullo M., Zuccarello F., Contarino L., Romano P.: A statistical approach to
the spot-flare connection, Proc of ”Magnetic coupling of the solar atmosphere SOLMAG” ESA SP-505, 591-594, 2002
[89] Ternullo M., Zuccarello F., Contarino L., Romano P.: A statistical analisys on
sunspot groups correlated to M and X flares, Proc of ”Solar variability: from core
to outer frontiers” ESA SP 506, 1045-1048
[90] Testi L, D’Antona F., Ghinassi F., Licandro J., Magazzù A., Natta A., Oliva E.:
NIR Low-Resolution Spectroscopy of L-Dwarfs: An Efficient Classification Scheme
for Faint Dwarfs, The Origins of Stars and Planets: The VLT View. Proceedings of
the ESO Workshop held in Garching, Germany, 24-27 April 2001, p. 187.
[91] Zerbi F. M., .Chincarini G.,Rodonò M., Ghisellini G., Antonelli, A., Conconi P.,
Covino S., Cutispoto G., Molinari, E.: REM – Rapid Eye Mount. A Fast Slewing
127
Robotized Telescope to Monitor the Prompt Infra-Red Afterglow of GRBs, Scientific Drivers for ESO Future VLT/VLTI Instrumentation Proceedings of the ESO
Workshop held in Garching, Germany, 11-15 June, 2001. p. 42, 2002
[92] Zuccarello F., Zappalà R.A.: Angular velocity of age-selected sunspot-groups over
the cycle Poster Proceedings of the ”First Potsdam Thinkshop on Sunspots and
Starspots” May, 6-10 2002, K.G Strassmeier and A. Washuettl (Eds), AIP, 131-132,
2002
7.3.1
In press
[93] V. Andretta, I. Busá, M. T. Gomez, S. Ragaini, L.Terranegra, Semi-empirical chromospheric models of late-type stars, IAU Symposium No. 210 in press
[94] Barstow M.A., and the WSO Team (Pagano I. enclosed): The World Space Observatory , XIII European Workshop on White Dwarfs, De Martino D., Silvotti R.,
Solheim J.-E. & Kalytis R. eds., NATO Science Series,Kluwer Academic Publishers,
in press
[95] Belluso M., Bonanno G., Calı̀ A., Carbone A., Cosentino R., Modica A., Scuderi S., Timpanaro C., Uslenghi M.:A new Photon Counting Detector: Intensified CMOS-APS Scientific Detectors for Astronomy - June 16-22, 2002 - Waimea,
Hawaii, in press
[96] Bonanno A., Belvedere G., Elstner D., Rüdiger G.: Parity properties of an
advection-dominated solar dynamo, Proc. 3deg Convegno sulla Ricerca Solare Italiana,Vulcano, 30 September - 4 October 2002, F. Zuccarello et al. (eds.), Mem. Soc.
Astr. It., in press
[97] Busà I., Pagano I., Rodonò M., Gomez, M.T., Andretta V., Terranegra L.: NLTE
line-blanketed Ca II IRT calculation for evaluation of GAIA spectroscopic performances, ASP Conf. Ser, U. Munari (ed), in press
[98] Contarino L., Romano P., Zuccarello F., Yurchyshyn V.B., An example of low-lying
magnetic reconnection observed by THEMIS, BBSO and TRACE, 3◦ Convegno sulla
Ricerca Solare Italiana (Vulcano - Isole Eolie, 2002), Mem. S.A.It., in press
[99] Cosentino R., Belluso M., Bonanno G., Bruno P., Bortoletto F.,
D’Alessandro M., Fantinel D., Giro E., Corcione L., Carbone A., Evola G.: The
new generation CCD controller: first results Scientific Detectors for Astronomy June 16-22, 2002 - Waimea, Hawaii, in press
[100] Cosentino R., Belluso M., Bonanno G., Scuderi S., Di Franco C., Fallica P.G.,
Sanfilippo D., Sciacca E., Lombardo S.: Preliminary test measurements of SPAD
array Scientific Detectors for Astronomy - June 16-22, 2002 - Waimea, Hawaii , in
press
[101] Costa V., Iapichino L., Zappalà R.A.: The P process in type II supernovae: current
status, Mem S.A.It., vol. 74, issue 1, in press
128
[102] Di Mauro M.P., Christensen-Dalsgaard J., Paternò L.:A study of the solar-like
properties of beta-Hydri 2002, in ”Asteroseismology across the HR diagram” Porto
, July 1-5, 2002, Portugal, Astrophysics and Space Science Series, ed. by Kluwer, in
press
[103] Di Mauro M.P., Pijpers F., Christensen-Dalsgaard J., Paternò L., Teixera T.,
Thompson M. J.: On the asteroseismic constraints for modeling the delta-Scuti
stars V480TAU and theta2 TAUA” in ”International Conference on magnetic fields
in O, B and A stars”, Mmabatho, Nov 27- Dec 1, 2002, South Africa ASP Conference
Series, Vol. N. 216, ed. by L. A Balona, H. F. Henrichs & T. Medupe, in press
[104] Di Mauro M.P., Paternò L.: Oscillations of the Sun: insights and challenges for
the future in 3deg Convegno sulla Ricerca Solare Italiana (Vulcano, 30 Settembre 4 Ottobre 2002), Mem. SaIt, ed. by F. Zuccarello, R. Ventura, D. Spadaro, in press
[105] Frasca A., Biazzo K., Catalano S., Marilli E.: Photospheric and Chromospheric
Active Regions from Line Depth Ratios and H-alpha Emission”, in New directions
for close binary studies: the royal road to the stars, proc. of Canakkale workshop
held in Dardanos Canakkale (Turkey) 24-28 June, 2002, in press
[106] Frasca A., Catalano S., Marino G., Marilli E., Messina S., Cutispoto G.,
Rodonò M.: Spots and plages on HK Lac, Poster Proceedings of the ”First Potsdam
Thinkshop on Sunspots and Starspots”, May, 6-10 2002, K.G Strassmeier and A.
Washuettl (Eds), AIP, in press
[107] Gheller C.,Becciani U., Ferro D., Melotti M., Calori L. The Cosmo.Lab project:
developing AstroMD, an object oriented, open source visualization and pre-analysis
tool for astrophysical data ADASS 2002 Baltimore (MD) 14-16 October 2002, in
press
[108] Gratton R.. Bonanno G, Bruno P., Cali A., Claudi R.U., Cosentino R.,
Desidera S., Diego F., Farisato G., Martorana G., Rebeschini M.,Scuderi S.: Sarg:
The high resolution spectrograph of TNG Experimental Astronomy - Kluwer Academic Publishers (EXPA459) , in press
[109] Gratton R., Carretta E., Claudi R.U., Desidera S.,. Lucatello S.,Bonanno G.,
Cosentino R., Scuderi. S., Barbieri M., Marzari F., Endl M., Brocato E., Dolci
M, Valentini The SARG Planet Search: hunting for planets around stars in wide
binaries Scientific Frontiers in Research on Extrasolar Planets, Washington 18-22
June 2002 ASP Conf. Series, in press
[110] Isik E., Frasca A., Aslan Z., Messina S., Catalano S.: Short and Long Term
Chromospheric Activity in the Triple System DH Leonis, in New directions for
close binary studies: the royal road to the stars, proc. of Canakkale workshop held
in Dardanos Canakkale (Turkey) 24-28 June, 2002, in press
[111] Lanza A. F. , Spadaro D., Lanzafame A. C., Karpen J. T., EUV line emission
from coronal loop models in thermal non-equilibrium, ”35th ESLAB Symposium:
Stellar Coronae in the Chandra and XMM-Newton Era” (ESTEC, Noordwijk, 2001),
eds. F. Favata, J. Drake, Astronomical Society of the Pacific Conference Series, CS
277, in press
129
[112] Lanzafame A.C., Busà I., Rodonò M.: Chromospheric two-component NLTE modelling of RS CVn systems, Modelling of Stellar Atmospheres IAU Symposium 210,
in press
[113] Lanzafame G., Costa V., Belvedere G.: SPH modelling of spiral shocks in viscous
and inviscid accretion discs in close binary systems, in Proc of the 8th IAU AsianPacific regional meeting, July 2-5, 2002 Tokyo Japan, in press
[114] Leone F.: The high resolution spectropolarimeter of the Italian Telescopio
Nazionale Galileo Third international workshop on”SOLAR POLARIZATION”
30th September- 4th October, 2002 Puerto de La Cruz, Tenerife, Spain Organized
by the Instituto de Astrofı́sica de Canarias ASP Conf. Series, in press
[115] Leone F., Bruno P., Calı̀ A., Claudi R., Cosentino R., Gentile G., Gratton R., Scuderi S.: High-Resolution Spectropolarimetry at the Italian Telescopio
Nazionale Galileo SPIE’ Astronomical Telescopes and Instrumentation 22 - 28 August 2002 Waikoloa, Hawai’i USA, in press
[116] Magazzù A., Dougados C., Licandro J., Martı́n E.L., Magnier E., Menard F.:
Infrared Spectra of Brown Dwarf Candidates in Taurus, Proceedings of the IAU
Symposium 211, ”Brown Dwarfs”, in press
[117] Magnier E.A., Dougados C., Ménard F., Martı́n E.L., Magazzù A.: A deep photometric search for substellar mass objects in Taurus, Proceedings of the IAU Symposium 211, ”Brown Dwarfs”, in press
[118] Messina S., Rodonò M., Cutispoto G.: A systematic search of starspots cycles
by robotic observations at Catania Astrophysical Observatory, Poster Proceedings
of the ”First Potsdam Thinkshop on Sunspots and Starspots” May, 6-10 2002, K.G
Strassmeier and A. Washuettl (Eds), AIP, in press
[119] Miglio A., Christensen-Dalsgaard J., Di Mauro M. P., Monteiro M. J. P. F. G,
Thompson M. J.: Seismological analysis of the second Helium ionization zone of the
stars, in ”Asteroseismology across the HR diagram” Porto , July 1-5,2002, Portugal,
Astrophysics and Space Science Series, ed. by Kluwer, in press
[120] Ragaini S., Andretta V., Gomez M.T., Terranegra L., Busà I., Pagano I.:GAIA
spectroscopy of active solar-type stars, ASP Conf. Ser, U. Munari (ed), in press
[121] Romano P., Contarino L., Zuccarello F., Instability analysis of an active prominence, 3◦ Convegno sulla Ricerca Solare Italiana (Vulcano - Isole Eolie, 2002), Mem.
S.A.It., in press,
[122] Spadaro D., Lanza A.F.: Simulations of transiently heated solar coronal loop,
3◦ Convegno sulla ricerca solare italiana, F. Zuccarello et al (Eds.), Vulcano, Sept.
30 – Oct. 4 2002 , MemSait, in press
[123] Spadaro D., Lanza A. F., Lanzafame A. C., Karpen J. T., Antiochos S. K., MacNeice P. J., Hydrodynamics of coronal loops undergoing transient heating, ”35th
130
ESLAB Symposium: Stellar Coronae in the Chandra and XMM-Newton Era” (ESTEC, Noordwijk, 2001), eds. F. Favata, J. Drake, Astronomical Society of the Pacific
Conference Series, CS 277, in press
[124] Ternullo M., Contarino L., Romano P., Zuccarello F.: The impact of the spotgroup age and lifetime on their capability of hosting M and X flares, 3◦ Convegno
sulla ricerca solare italiana, F. Zuccarello et al (Eds.), Vulcano, Sept. 30 – Oct. 4
2002 , MemSait, in press
[125] Uslenghi M. C.,Bonanno G., Belluso M., Calı̀ A., Timpanaro C., Cosentino
R., Scuderi S., Modica A.:Progress report on the photon counting intensified
APS Future EUV-UV and Visible Space Astrophysics Missions and Instrumentation
Proceedings of SPIE Vol. #4854, in press
[126] Zuccarello F., Contarino L., Romano P., Ternullo M.: Program of solar observations and flare warning at Catania Astrophysical Observatory, Proc. of ”Space
weather workshop” ESA WPP 194, in press
[127] Zuccarello F., Zappalà R.A., Angular velocity of sunspot-groups during the activity
cycle deduced using the age selection methodology, 3◦ Convegno sulla Ricerca Solare
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[128] Becciani U., Antonuccio-Delogu V. :FLY: a parallel multi-platform code for
cosmological simulations, Science and Supercomputing at CINECA, 3-9, 2001 M.
Voli Report 2001
[129] Becciani U., Antonuccio-Delogu V., Gheller C., Calori L., Buonomo F., Imboden S.: AstroMd. A multi-dimensional data analysis tool for cosmological simulations, Science and Supercomputing at CINECA, 25-29, 2001 M. Voli Report 2001
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a
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Document
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test
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[133] Di Franco C., Sanfilippo D., Cosentino R., Sciacca E., Belluso M.: Single Photon
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[135] Frasca A., Cakirli O., Catalano S., Ibanoglu C., Marilli E., Evren S., Tas G.:
BV photometry of RT Lac, VizieR On-line Data Catalog: J/A+A/388/298.
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[137] Marino G., Catalano S., Frasca A., Marilli E., Teriaca L.: Radial velocities and
orbital solution of the active binary star FG Ursae Majoris, Information Bulletin
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[138] Messina S., Guinan E.F.: Starspot cycles of six young solar analogues Vizier Online Data Catalog: J/A+A/393/225
[139] Noci G., Caccin B., Peres G., Spadaro D.: Italian Solar Physics, documento del
gruppo di lavoro dell’area ”Sole: struttura interna, atmosfera e vento solare; attività
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[140] Paternò L.: Lucrezio e il De rerum natura, Giornale di Astronomia,vol. 28., n.3
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[141] Zuccarello F., Contarino L., Romano P., Bonanno G., Spadaro D., Ternullo
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132
Appendix A
Sommario del bilancio OACt 2002
La gestione del bilancio dell’ esercizio finanziario 2002, come negli anni precedenti è
stata improntata alla massima attenzione al risparmio sulle spese di funzionamento ordinario da una parte ed alla acquisizione di nuove attrezzature necessarie per il conseguimento degli obbiettivi istituzionali dell’ OACt. L’attività svolta trova positivo riscontro
nell’acquisizione di attrezzature di notevole impegno economico, effettuata utilizzando
anche risparmi di bilancio degli anni precedenti, nel miglioramento di quelle esistenti, ed
inoltre nei risultati conseguiti che sono illustrati in questo rapporto.
È da rilevare in via preliminare che, sia il conto consuntivo relativo all’esercizio 2001
che il bilancio preventivo 2002 sono stati gestiti in termini di competenza, mentre il conto
consuntivo del 2002 in conformità all’ art. 23 del Regolamento sulla Amministrazione,
contabilità e attività contrattuale dell’ INAF è stato richiesto che venisse gestito in termini
di Cassa. Ciò comporta una differente presentazione dell’ avanzo di amministrazione tra
entrate e uscite.
Il bilancio con la sua forma finale delle previsioni definitive delle entrate e delle spese
(vedi Tabelle A.1 ed A.2) si è realizzato apportando variazioni in diverse sedute del
CdO, essenzialmente per regolarizzare nuove entrate (UE, ASI, MIUR, INAF etc.) e
per adeguare alcuni capitoli di spesa.
Table A.1: Entrate (in kEU)
Entrate definitive Riscosse
Avanzo di amministrazione
Fondo cassa
Assegnazione funzion.
Rimborsi vari
ASI
Unione Europea
Trasfer. da enti Pubblici
Partite di giro
Totale entrate
342
3.231
3.389
4
79
14
123
1.834
9.016
342
3.231
2.851
4
79
14
123
836
7.480
Da riscuotere
538
20
558
La situazione amministrativa evidenzia la consistenza del fondo di cassa in 2.033.373,48
alla fine dell’esercizio finanziario 2002, come scaturisce dalla scritture contabili e in accordo con le risultanze dell’Istituto cassiere ed un avanzo di amministrazione determinato
133
134
APPENDIX A. SOMMARIO DEL BILANCIO OACT 2002
Descrizione
Table A.2: Spese (KEU)
Previsioni definitive
Spese per Organi della strutt.
Oneri per il Personale
Spese per acquisto di beni e serv.
Spese correnti per la ricerca
spese per la ricerca a dest. vincolata
Oneri e tributi
Spese diverse
Acquisti e manut. straord.
Spese di investim. per la ricerca
Edilizia (impegni vincolati)
Spese di invest. a dest. vincolata
Rimborso mutui
Partite di giro
Totale
25
2.773
431
435
494
8
18
133
636
1.788
483
5
1.786
9.016
Pagate
23
2.748
347
326
308
7
0
91
415
125
243
5
809
5.447
in 98.285,28, risultante dalla disponibilità di cassa alla chiusura dell’attività e della somma
algebrica dei crediti e dei debiti (impegni assunti entro al fine dell’anno, qui non riportati
ma allegati al Conto consuntivo).
Il fondo di cassa è essenzialmente costituito da fondi a destinazione vincolata (ASI,
Regione, UE ecc.) e nella massima parte dalle assegnazioni e gli impegni di spesa inerenti
a lavori edilizi, la cui realizzazione e molto spesso frenata dai numerosi adempimenti
necessari e dalla lentezza degli iter burocratici.
Dal semplice punto di vista economico, l’esercizio finanziario 2002 si è chiuso con una
significativa riduzione dell’avanzo di amministrazione. Ciò è stato determinato da tre
fattori principali: a) le maggiori spese intervenute a seguito dei lavori di ristrutturazione
dell’edificio della sede della città universitaria (trasloco e affitto deposito, disattivazione
e riconfigurazione impianti) b) acquisizione di attrezzature per la ricerca da tempo programmate e finalmente realizzate (es. il potenziamento dell’impiantatore di ioni fino a
200 keV) c) l’ aumento dei prezzi.
Mentre dai due maggiori fattori di spesa ci si aspetta delle ricadute positive in quanto
si realizza da una parte un nuovo strumento di ricerca all’avanguardia, e dall’altra un
significativo miglioramento degli ambienti di lavoro, la progressiva riduzione dell’avanzo
di amministrazione, accompagnata alla riduzione dei finanziamenti si riflette negativamente sulla possibilità di ulteriori miglioramenti delle attrezzature e delle strutture e sul
mantenimento dell’attività di ricerca stessa agli attuali livelli di eccellenza.

INAF Osservatorio Astrofisico di Catania Annual Report 2002

Transcript

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