by Maria Isabel Carnerero
The third release of Gaia data, published on June 13, 2022, includes not only astrometric and astrophysical parameters of different types of sources, but also several catalogues of variable sources.
Maria Isabel Carnerero & Claudia M. Raiteri, in collaboration with several authors, including Deborah Busonero, Enrico Licata and Mario Lattanzi from the OATo, have published the first Gaia catalogue of variable active galactic nuclei (AGN). For this work they analyzed the light curves of more than 80 million sources observed by Gaia, selecting 870 thousands of them through a series of requests on their variability properties, colour indices, astrometric parameters and others. The purpose was to create a variable AGN catalogue as pure as possible. More than 21,000 of these 870 thousand sources (about 2.5% of the total) are identified as variable AGN for the first time.
In the paper, the infrared and radio emission of the sources is also analysed.
Finally, the possibility to estimate the time lag between the flux variations in the light curves of the different images of a gravitationally lensed quasar is explored.
For each source of the catalogue, the multiband light curves and the values of the variability parameters have been included in the database.
The article “Gaia Data Release 3: The first Gaia catalog of variable AGN“ by Carnerero, Raiteri et al. was published in Astronomy & Astrophysics.
Figure: Sky distribution of the sources in the Gaia catalogue of variable AGN. (Credits: Carnerero et al. 2022)
