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National Solar Observatory
Global Oscillation Network Group |
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Simultaneous Velocity-Intensity Fitting (2003)
We use 9 GONG months (324 days, from 1996 Oct. 28 to 1997 Sept. 16,
duty cycle=85%) of I (Intensity) and V (Velocity)
rotation corrected,
m-averaged spectra corresponding to
l=15-50
between 1.6 and 4.8 mHz (617 modes) to determine the solar oscillation
parameters. These parameters are determined by fitting simultaneously 4
spectra: V and I power, I-V phase difference and I-V coherence using the
model of Severino et al. (2001). More details are in
Barban et al. (2003).. |
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The figure at left shows the good fit to the observed
spectra for the l=24, n=9 mode, with the dots showing the data and
the curves the fit. |
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Here we show the modeled helioseismic spectra for
l=24, n=9,
demonstrating the sensitivity to the background components.
The solid line corresponds to the best fit; the dashed line to the
same model with the coherent uncorrelated background set to zero
both in I and V, and the dotted line to a model
with the coherent correlated background set to zero.
The absolute oscillation frequency
difference is less than 0.1 microHz between 1.6 and 3.2 mHz.
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