Rate of correct detection of periodic signal with the Gaia satellite

Eyer, L. ; Mignard, F.

In: Monthly Notices of the Royal Astronomical Society, 2005, vol. 361, no. 4, p. 1136-1144

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    The Gaia satellite was selected as a cornerstone mission of the European Space Agency (ESA) in 2000 October and confirmed in 2002 with a current target launch date of 2011. The Gaia mission will gather on the same observational principles as Hipparcos detailed astrometric, photometric and spectroscopic properties of about one billion sources brighter than V= 20 mag. The nature of the measured objects ranges from near-Earth objects (NEOs) to gamma-ray burst afterglows, and encompasses virtually any kind of stars in our Galaxy. Gaia will provide multicolour (in about 20 passbands extending over the visible range) photometry with typically 250 observations distributed over 40 well-separated epochs during the 5-yr mission. The multi-epoch nature of the project will permit the detection and analysis of variable sources whose number is currently estimated in the range of several tens of millions, among the detectable sources. In this paper, we assess the performances of Gaia in analysing photometric periodic phenomena. We first quickly present the overall observational principle before discussing the implication of the scanning law in the time-sampling. Then from extensive simulations one assesses the performances in the recovery of periodic signals as a function of the period, signal-to-noise ratio and position on the sky for simple sinusoidal variability