34th Solar Physics Division Meeting, June 2003
Session 26 The Changing Solar interior II
Oral, Friday, June 20, 2003, 9:00am-12:00noon, Auditorium

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[26.10] Estimates of helioseismic oscillation excitation parameters from multi-spectral fitting.

C. Barban, F. Hill (National Solar Observatory)

The solar oscillation parameters, as the frequency, are usually determined by fitting a theoretical profile to the observed Doppler velocity (V) power spectrum. We present here the solar oscillation parameters determined using GONG V data as well as Intensity (I) data. To do that, we used Severino et al. (2001, ApJ 561,444) model to reproduce the following 4 helioseismic spectra: V and I power spectrum, I-V phase difference and coherence spectra. This model is based on a coherent resonant p-mode signal; two coherent background components, one correlated and one uncorrelated to the oscillation modes; and, finally, the uncoherent noise. Using this model, we have fitted simultaneously the 4 helioseismic spectra mentioned above for several hundreds modes between l=15 and 50 and for 9 GONG months rotation corrected m-average data around the solar minimum. The solar oscillation parameters (frequency, amplitude and width) obtained by this way will be presented as well as a comparison with the results obtained using only V data. The study of the background components used in the model with the aim of better understanding the solar oscillation excitation mechanism will be addressed.

This work is supported by NASA grant NAG5-11703.


The author(s) of this abstract have provided an email address for comments about the abstract: barban@noao.edu

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