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Astron. Astrophys. 345, 1027-1037 (1999)

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Solar low-degree p-mode parameters from the GONG network

M.C. Rabello-Soares 1 and T. Appourchaux 2

1 Teoretisk Astrofysik Center, Danmarks Grundforskningsfond and Institut for Fysik og Astronomi, Aarhus Universitet, DK-8000 Aarhus C, Denmark (csoares@obs.aau.dk)
2 Space Science Department of ESA, ESTEC, 2200 AG Noordwijk, The Netherlands (thierrya@so.estec.esa.nl)

Received 10 November 1998 / Accepted 18 February 1999


Low-degree solar p modes observed by the GONG network have been analysed for [FORMULA], yielding accurate measurements of their frequencies, splittings and linewidths. The results obtained here show significant improvement on previous determinations, especially for increasing the number of identified modes with [FORMULA] and for minimizing the bias on the splitting determination and the error bars. A more realistic approach was used to fit the helioseismic data assuming that the observed spectra are statistically dependent upon one another. This is in contrast to what is commonly done and the result is a better treatment of the leakage between the modes. Moreover, the effect of an imperfect knowledge of the leakage within the elements of the [FORMULA] multiplets upon their splitting determination is analysed. In addition, the effect of the leakage between the modes of different degrees upon the p-mode parameters determination is shown, and a procedure for `cleaning' the spatial alias is described leading to splitting coefficients with smaller systematic errors than before.

Key words: Sun: oscillations – methods: data analysis – methods: observational

Send offprint requests to: M.C. Rabello-Soares

© European Southern Observatory (ESO) 1999

Online publication: April 28, 1999