The Solar Acoustic Spectrum as Seen by Golf

Data acquired by GOLF experiment onboard SOHO during 20 months has been analysed. GOLF is a disk-integrated sunlight experiment therefore biased to observe very low`modes (` 3). However the excellent ratio signal to background (S=B) achieved permits also the detection of some modes with 4 ` 6 and those from n 8 up to the cut-oo frequency and even beyond with the pseudomodes signal. Due to the nature of the excitation function of the modes (which we will call noise) the line shapes look "spiky" rising the possibility (the necessity?) to use several methods of analysis of such data: a) FFT spectrum and maximum likelihood tting technique, b) averaged FFT spectra of subseries and least squares tting technique, c) HD spectra and least squares t. Moreover, as a consequence of the characteristics of the spectrum: 1 S=B 10 4 , linewidths of 0:1 ? 40Hz and the presence of noise, several t strategies have to be deened in order to t appropriately and accurately the mode line shapes. In this poster these methods and t strategies will be explained and comparative results will be presented.