Low-Order p Modes From Virgo Irradiance Data

Several candidates for low-order p modes (n ≤ 5) and possibly g modes were found by applying mode-detection techniques such as multivariate spectral regression analysis and time-frequency analysis to the VIRGO full-disc solar irradiance data. Three out of the candidates for low-order p modes could be confirmed by significant peaks in the un-treated power spectra in good agreement with theoretical predictions. The frequency of a fourth candidate for a low-order p mode lies some 2.8 μHz below the predicted frequency. The candidates found for g modes are less reliable, since none of them could be confirmed neither by significant peaks in the un-treated power spectra nor by the detection of multiplets.