  We present results of time-series data simulation. We aimed at estimating the
threshold used for detecting signals in amplitude spectra, calculated from
simulating TESS photometry of up to one year duration. We selected the
threshold at a false alarm probability FAP=0.1% and derived S/N ratios between
4.6 and 5.7 depending on the data cadence and coverage. We also provide a
formula to estimate the threshold for any FAP adopted and a given number of
data points. Our result confirms that, to avoid spurious detection, space-based
photometry may require substantially higher S/N than that typically being
employed for ground-based data.

Instrumentation and Methods for Astrophysics