The analysis of indexed astronomical time series V. Fitting sinusoids to high-speed photometry |
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| Authors: | Chris Koen |
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| Institution: | South African Astronomical Observatory, PO Box 9, Observatory, 7935 Cape, South Africa |
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| Abstract: | The estimation of the frequency, amplitude and phase of a sinusoid from observations contaminated by correlated noise is considered. It is assumed that the observations are regularly spaced, but may suffer missing values or long time stretches with no data. The typical astronomical source of such data is high-speed photoelectric photometry of pulsating stars. The study of the observational noise properties of nearly 200 real data sets is reported: noise can almost always be characterized as a random walk with superposed white noise. A scheme for obtaining weighted non-linear least-squares estimates of the parameters of interest, as well as standard errors of these estimates, is described. Simulation results are presented for both complete and incomplete data. It is shown that, in finite data sets, results are sensitive to the initial phase of the sinusoid. |
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| Keywords: | methods: data analysis methods: statistical |
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