19.6 Scan-angle dependent signals and spurious periods

The ongoing processing and analyses of Gaia data by DPAC and the scientific community is leading to a more detailed understanding of the Gaia data, processing steps, and potential artefacts in its data products. In Holl et al. (2023a) we focus on the occurrence of the so-called scan-angle dependent signals in the Gaia data, as well as some other disturbances which, when left unmodelled (as in Gaia DR3), can lead to artefacts in the Gaia data products like the occurrence of spurious periodic behaviour. We discuss the background of these artefacts, identification diagnostic statistics, and provide suggestions on how to deal with them.

For 11 754 237 sources with published photometric time series in Gaia DR3 (i.e., sources in gaia_source with has_epoch_photometry =TRUE), the archive table vari_spurious_signals provides the user with several diagnostic statistics related to the potential identification of anomalous artefacts and spurious periods in the photometric data products. Note that these sources are either variable sources (Eyer et al. 2023) or part of the Gaia Andromeda Photometric Survey (GAPS, see Evans et al. 2023) and can be identified in both gaia_source and vari_spurious_signals by phot_variable_flag =VARIABLE and in_andromeda_survey =TRUE, respectively.