Gaia Data Release 3: Microlensing Events from All Over the Sky

TL;DR

This paper presents the first Gaia catalogue of 363 microlensing events detected across the entire sky over 34 months, including 90 new discoveries, demonstrating Gaia's capability to identify such rare phenomena.

Contribution

The paper introduces the first Gaia microlensing catalogue, analyzing 2 billion sources and validating 363 events, with 90 being novel discoveries not found in previous surveys.

Findings

Identified 363 microlensing events from Gaia DR3 data.

Discovered 90 new microlensing events not reported before.

Estimated contamination rate of the catalogue to be 0.6-1.7%.

Abstract

Context: One of the rarest types of variability is the phenomenon of gravitational microlensing, a transient brightening of a background star due to an intervening lensing object. Microlensing is a powerful tool in studying the invisible or otherwise undetectable populations in the Milky Way, including planets and black holes. Aims: We describe the first Gaia catalogue of microlensing event candidates, give an overview of its content and discuss its validation. Methods: The catalogue of Gaia microlensing events is composed by analysing the light curves of around 2 billion sources of Gaia Data Release 3 from all over the sky covering 34 months between 2014 and 2017. Results: We present 363 Gaia microlensing events and discuss their properties. Ninety events were never reported before and were not discovered by other surveys. The contamination of the catalogue is assessed to 0.6-1.7%.