Nami Mowlavi

Photometric variability is an essential feature that shed light on the intrinsic properties of celestial variable sources, the more so when photometry is available in various photometric bands. In this respect, the all-sky Gaia mission is particularly attractive as it collects, among other quantities, epoch photometry measured quasi-simultaneously in three optical bands for sources ranging from a few magnitudes to fainter than magnitude twenty. The second data release (DR2) of the Gaia mission has provided mean photometry in the three photometric bands for about 1.4 billion sources, but light curves and variability properties are available in that release for only ~0.5 million of them. Variable sources with large enough amplitudes are nevertheless identifiable from the data published in DR2.

This has been done in the paper Mowlavi et al. (2020) which provides a catalogue of 23'315'874 large-amplitude variable candidates with variability amplitudes greater than about 0.2 magnitudes. A multi-band variability analysis of the catalogue presented in the paper shows how different types of variable stars can be globally categorized in four groups according to their colour and blue-to-red variability amplitude ratios.

The catalogue of large-amplitude variables has 23'315'874 rows and 39 columns, and is available in 2 formats for download at http://obswww.unige.ch/~mowlavi/Data/ :