  We analyzed the frequency domain of time series of simulated ZZ Ceti
light-curves to investigate the detectability and period recovery performance
of short period variables (periods < 2 hours) for the Gaia mission. In our
analysis, first we used a non-linear ZZ Ceti light-curves simulator code to
simulate the variability of ZZ Ceti stars (we assumed stationary power spectra
over five years). Second we used the Gaia nominal scanning law and the expected
photometric precision of Gaia to simulate ZZ Ceti time series with Gaia's time
sampling and photometric errors. Then we performed a Fourier analysis of these
simulated time series. We found that a correct period can be recovered in ~65%
of the cases if we consider Gaia per CCD time series of a G ~ 18 magnitude
multiperiodic ZZ Ceti star with 5%-10% light-curve variation. In the
pre-whitened power spectrum a second correct period was also recovered in ~26%
of the cases.
