Photometric Science Alerts from Gaia

TL;DR

Gaia's Photometric Science Alerts system will detect and classify astronomical transients like supernovae and microlensing events in near-real-time, enabling rapid follow-up observations and advancing our understanding of transient phenomena.

Contribution

This paper details Gaia's alert system operation, its scientific potential, and invites collaboration for ground-based follow-up during early mission phases.

Findings

Expected detection of about 6000 supernovae

Identification of approximately 1000 microlensing events

Robust classification with low false-alert rate

Abstract

Gaia is the cornerstone mission of the European Space Agency. From late 2013 it will start collecting superb astrometric, photometric and spectroscopic data for around a billion of stars of our Galaxy. While surveying the whole sky down to V=20mag Gaia will be detecting transients and anomalous behaviour of objects, providing near-real-time alerts to the entire astronomical community. Gaia should detected about 6000 supernovae, 1000 microlensing events and many other interesting types of transients. Thanks to its on-board low-dispersion spectrograph the classification of transients will be robust, assuring low false-alert rate. We describe the operation of the Photometric Science Alerts system, outline the scientific possibilities and conclude with an invitation to collaborate in the ground-based follow-up Gaia alerts during the early months of the mission when the outcome of the alerting pipeline needs to be verified.