Dark lens candidates from Gaia Data Release 3

TL;DR

This paper identifies potential dark stellar remnants like white dwarfs, neutron stars, black holes, and mass-gap objects through analysis of Gaia DR3 microlensing data, providing candidates for further study.

Contribution

It introduces a method to select and estimate masses of dark remnant candidates from Gaia DR3 microlensing events, expanding the search for non-luminous stellar remnants.

Findings

Identified 11 dark remnant candidates including WDs, NS, mass-gap objects, and BHs.

Estimated masses of candidates based on microlensing models and galactic data.

Provided a new catalog of potential dark stellar remnants for future observations.

Abstract

Gravitational microlensing is a phenomenon that allows us to observe dark remnants of stellar evolution even if they no longer emit electromagnetic radiation. In particular, it can be useful to observe solitary neutron stars or stellar-mass black holes, providing a unique window through which to understand stellar evolution. Obtaining direct mass measurements with this technique requires precise observations of both the change in brightness and the position of the microlensed star. The European Space Agency's Gaia satellite can provide both. Using publicly available data from different surveys, we analysed events published in the Gaia Data Release 3 (Gaia DR3) microlensing catalogue. Here we describe our selection of candidate dark lenses, where we suspect the lens is a white dwarf (WD), a neutron star (NS), a black hole (BH), or a mass-gap object, with a mass in a range between the heaviest NS and the least massive BH. We estimated the mass of the lenses using information obtained from the best-fitting microlensing models, the source star, the Galactic model and the expected distribution of the parameters. We found eleven candidates for dark remnants: one WDs, three NS, three mass-gap objects, and four BHs.