Gaia: switching “ON” the transient discovery machine

The Gaia Photometric Science Alerts (GSA) group is the Gaia Data Processing and Analysis Consortium (DPAC) unit responsible for releasing alerts on Gaia transient candidates from a daily flow of initially reduced data. In preparation for obtaining the rates for different transient families with Gaia, one of the main goals of GSA is to reliably identify and characterize the candidates. In this article, we describe the simulations used to understand and predict possible selection effects and the techniques used to identify the nature of the transient alerts provided by Gaia.