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  • Research Article
  • Open Access

Time-Scale and Time-Frequency Analyses of Irregularly Sampled Astronomical Time Series

EURASIP Journal on Advances in Signal Processing20052005:852587

https://doi.org/10.1155/ASP.2005.2486

Received: 27 May 2004

Published: 14 September 2005

Abstract

We evaluate the quality of spectral restoration in the case of irregular sampled signals in astronomy. We study in details a time-scale method leading to a global wavelet spectrum comparable to the Fourier period, and a time-frequency matching pursuit allowing us to identify the frequencies and to control the error propagation. In both cases, the signals are first resampled with a linear interpolation. Both results are compared with those obtained using Lomb's periodogram and using the weighted wavelet -transform developed in astronomy for unevenly sampled variable stars observations. These approaches are applied to simulations and to light variations of four variable stars. This leads to the conclusion that the matching pursuit is more efficient for recovering the spectral contents of a pulsating star, even with a preliminary resampling. In particular, the results are almost independent of the quality of the initial irregular sampling.

Keywords and phrases

  • astronomical time series
  • irregular sampling
  • time-scale methods
  • time-frequency methods
  • wavelets
  • matching pursuit

Authors’ Affiliations

(1)
Centre d'Etude Spatiale des Rayonnements, Toulouse Cedex 4, France
(2)
Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées, Toulouse, France

Copyright

© C. Thiebaut and S. Roques 2005

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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