EDP Sciences
Free access
Volume 394, Number 1, October IV 2002
Page(s) 285 - 297
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20021106

A&A 394, 285-297 (2002)
DOI: 10.1051/0004-6361:20021106

Solar ${\vec p}$-modes from 1979 days of the GOLF experiment

B. Gelly1, M. Lazrek1, 2, 3, G. Grec3, A. Ayad1, 4, F. X. Schmider1, C. Renaud3, D. Salabert1 and E. Fossat1

1  Laboratoire d'Astrophysique, UMR 6525 du CNRS, Université de Nice-Sophia Antipolis, 06108 Nice Cedex 2, France
2  C.N.R., 52 Charii Omar Ibn El Khattab, BP 8027, Rabat, Morocco
3  Département Cassini, UMR 6529 du CNRS, Observatoire de la Côte d'Azur, 06304 Nice, France
4  Laboratoire de Physique des Hautes Énergies et Astrophysique, Université Cadi Ayyad, Marrakech, Morocco

(Received 26 March 2002 / Accepted 10 July 2002)

With the GOLF instrument onboard the SoHO observatory, 1979 days of full-disc Doppler velocity observations have been compiled into a study of p-mode properties. We develop a multi-step iterative method (MSIM) algorithm to access all p-mode parameters while minimizing any perturbating effect or cross-talk between parameters during their determination. We present frequency and splitting tables, amplitudes, linewidths, line asymmetries, pseudo-modes, and background noise determinations. We have a first look at the changes induced by the transition from the low-activity to the high-activity part of solar cycle 23: we have recorded frequency shifts with a downturn at 3.7 mHz followed by a possible higher upturn, and linewidth changes to a good accuracy. We detect an effect on the noise background at 3 mHz possibly related to an interaction between noise and the modes and connected to the asymmetry of the profiles.

Key words: Sun: oscillations -- Sun: helioseismology

Offprint request: B. Gelly, gelly@unice.fr

© ESO 2002