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Astron. Astrophys. 323, 235-242 (1997)
Solar P-mode frequencies from the IRIS network
B. Gelly 1,
D. Fierry-Fraillon 1,
E. Fossat 1,
P. Palle 2,
A. Cacciani 3,
S. Ehgamberdiev 4,
G. Grec 5,
J.T. Hoeksema 6,
S. Khalikov 4,
M. Lazrek 5, 7,
S. Loudagh 1,
A. Pantel 1,
C. Regulo 2 and
F.X. Schmider 1
1 Département d'Astrophysique, URA CNRS 709,
Université des Sciences, F-06108 Nice Cedex 2, France
2 Instituto de Astrofisica de Canarias, E-38071 La Laguna,
Tenerife, Spain
3 Dipartimento di Fisica dell'Università, Piazzale
Aldo Moro 2, I-00185 Roma, Italia
4 Astronomical Institute of the Uzbek Academy of Sciences,
Astronomicheskaya 33, Tashkent-700052, Uzbekistan
5 Département Cassini, URA CNRS 1362, Observatoire
de la Côte d'Azur, B.P. 229, F-06304 Nice Cedex 4, France
6 Center for Space Science and Astrophysics, Stanford
University, Stanford, CA 94305, USA
7 Laboratoire d'Astronomie du CNCPRST, BP 1346, Rabat,
Morocco
Received 24 September 1996 / Accepted 23 December 1996
Abstract
The Iris network for helioseismology has operated since 1989. We
present tables of solar p-mode frequencies for observations taken
during the four summer seasons from 1989 to 1992. This analysis uses
the technique of maximum likelihood fitting and a
![[FORMULA]](img1.gif)
model for the probability density function of
the spectrum. The simultaneous fitting of odd and even pairs of peaks
strengthens the identification of the ![[FORMULA]](img2.gif)
eigenmodes
and improves the error bars on the 0-2 group. The frequencies are in
good agreement with other observational results and with theoretical
values for the ![[FORMULA]](img3.gif)
and the ![[FORMULA]](img4.gif)
parameters of the asymptotic approximation. A decrease of
![[FORMULA]](img5.gif)
![[FORMULA]](img6.gif)
is seen between the 1989
and the 1992 data sets. The change is associated with the decrease of
solar activity and is comparable with results of previous studies.
Key words: Sun: oscillations; activity
Send offprint requests to: gelly@irisalfa.unice.fr
Contents
- 1. Introduction
- 2. IRIS full disk data and analysis
- 3. Peak parameter extraction techniques
- 3.1. Power spectrum modeling
- 3.2. Fitting technique
- 3.3. Error bars in frequency
- 4. Comparisons and results
- 4.1. -
![[FORMULA]](img64.gif)
diagram - 4.2. Solar cycle effects
- 4.1.
- 5. Conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 1997
Online publication: June 5, 1998
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