[7.05] Reconstructing Cepheid Light Curves with Fourier techniques

AAS 200th meeting, Albuquerque, NM, June 2002
Session 7. Variable Stars and Relatives
Display, Monday, June 3, 2002, 9:20am-6:30pm, SW Exhibit Hall

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[7.05] Reconstructing Cepheid Light Curves with Fourier techniques

C. C. Ngeow, S. M. Kanbur (University of Massachusetts)

Cepheid PL relations are used to determine the extra-galactic distance scale. Accurate distances to a target galaxy can be measured if the mean luminosity (or magnitude) of the Cepheid can be obtained accurately by reconstructing the entire light curve. For those Cepheids that have more than 10 observed data points, we use a fourth order Fourier expansion to reconstruct the light curve. In the case of HST I band observations, linear relations linking the Fourier parameters in the V and I band can be used to construct the I band light curve. Since the Fourier amplitudes (A_i) occupy certain ranges in the A_i-log(P) plane, the quality of the reconstructed light curve can be improved with appropriate choice for the ranges of Fourier amplitudes. We have carried out these procedures for the Cepheids observed by the HST as a prelude to recalibrating the extra-galactic distance scale.

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