Inferred acoustic rates of solar p modes from several helioseismic instruments

¹ Institut d'Astrophysique Spatiale, CNRS/Université Paris XI UMR 8617, 91405 Orsay Cedex, France e-mail: frederic.baudin@ias.u-psud.fr
² Observatoire de Paris, LESIA, CNRS UMR 8109, 92195 Meudon, France
³ Observatório Astronómico UC, FCTUC, Coimbra, Portugal
⁴ European Space Agency, Research and Science Support Department, Science Payload and Advanced Concept Office, PO Box 299, 2200Ag Noordwijk, The Netherlands
⁵ National Solar Observatory, 950 N. Cherry Avenue, Tucson AZ 85719, USA
⁶ School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK

Received: 4 May 2004
Accepted: 13 November 2004

Abstract

Acoustic rates of excitation of solar p modes can be estimated from observations in order to place constraints on the modelling of the excitation process and the layers where it occurs in the star. For several reasons (including a poor signal to noise ratio and mode overlap), this estimation is difficult. In this work, we use three completely independent datasets to obtain robust estimates in the solar case for modes. We also show that the height in the solar atmosphere where the modes are observed must be taken into account. Our three sets of results are shown to be consistent, particularly in the lower part of the p-mode spectrum (from 1.8 mHz to 2.8 mHz). At higher frequencies, the agreement is not as good, because of a larger dispersion of the measurements and also because of some systematic differences which might be due to observation height estimation or to a systematic influence of the noise.