The input sample comprised only those sources for which per-CCD data was available in
the Cycle 2 photometry provided by CU5 and which satisfied 20 -FoV transits, to ensure a
reliable variogram analysis. At this time of the Gaia processing, CU7 receives
per-CCD time series only for sources with more than half of their FoV transits
identified as ‘noisy’ according to their p-value from the 9 CCD measurements of the
considered transit (the limit defining a noisy transit being p-value below 0.01).
The analysis focused on faint sources with a mean magnitude in the range
16.5–20 mag as it is in this range that a relevant and validated detection criterion
can be obtained for short timescale candidates based on the variogram analysis.