Cross-spectral analysis of solar oscillation time series

Abstract

Spatial leakage is an unavoidable artifact in the extraction of solar oscillation modes by spheric harmonic decomposition from the wavefield observed on the solar surface. The determination of solar frequencies by spectral analysis is therefore greatly affected by spatial leakage. Here we show in which way spatial leakage also influences the cross-spectra between different solar oscillation modes. Simulations show that spatial leakage induces significant coherences between oscillations of degree I and I + 2 with low azimuthal order m. © 2008 IOP Publishing Ltd.