Analysis of GOLF Power Spectra Weighted to Account for Noise Variations Through the Data Set
Abstract
It has been established that the noise in Doppler velocity measurements obtained by resonant scattering spectrometers varies with season of the year and, of course, with instrument conditions. For example, recent analysis has characterized the noise in data taken by the Global Oscillations at Low Frequencies (GOLF) instrument on the ESA/NASA satellite SoHO, which shows seasonal variation and a secular increase associated with the degradation of GOLF's photomultiplier tubes. Using the noise characteristics it is possible to generate power spectra using the weighted sine-wave fit technique often employed in asteroseismic work. This paper presents the first analyses of such weighted power spectra, which have been generated from several years of GOLF data, and compares the results generated by more commonly employed unweighted transform techniques.
- Publication:
-
Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21
- Pub Date:
- December 2009
- Bibcode:
- 2009ASPC..416..325N