Low-frequency solar p modes as seen by GOLF and GONG instruments

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dc.creatorSalabert, D.
dc.creatorGarcia, R. A.
dc.date2008-10-09
dc.date2008-10-13
dc.date.accessioned2026-07-07T10:09:01Z
dc.date.available2026-07-07T10:09:01Z
dc.descriptionIn the case of spatially-revolved helioseismic data (such as MDI, GONG, HMI), the usual mode-fitting analysis consists of fitting the 2l+1 individual m-spectra of a given multiplet (n, l) either individually or simultaneously. Such fitting methods fail to obtain reliable estimates of the mode parameters (frequency, splitting, ...) when the signal-to-noise ratio (SNR) is low, which makes those methods not suitable when one wants to look at the low-amplitude, long-lived solar p modes in the low-frequency range. Instead, Salabert et al. (2007) developed a new method to extract the mode parameters by adjusting the rotation- and structure-induced frequency shift for each m-spectrum to minimize the mode width in the m-averaged spectrum (a "collapsogram"). The m-averaged spectrum technique, applied to the spatially-resolved GONG and MDI data, appeared to be a powerful tool for low SNR modes in the low-frequency range. Another possibility to increase the SNR is to combine data from different instruments (Garcia et al. 2004a). We present here an adaptation of both techniques: the "collapsograms" applied to a combination of observations from a Sun-as-a-star instrument, GOLF, and a disk-imaged one, GONG.
dc.description4 pages, 5 figures, Conference proceeding GONG 2008 / SOHO XXI Meeting
dc.identifierhttps://arxiv.org/abs/0810.1696
dc.identifierhttp://arxiv.org/abs/0810.1696
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/171197
dc.subjectAstrophysics
dc.titleLow-frequency solar p modes as seen by GOLF and GONG instruments
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