Name: Chirag Chawla
Affiliation: Tata Institute of Fundamental Research
Conference ID : ASI2022_282
Title : Gaia should detect hundreds of well-characterised black holes
Authors : Chirag Chawla, Sourav Chatterjee, Katelyn Breivik, Chaithanya Krishna Moorthy, Jeff J. Andrews, Robyn E. Sanderson
Abstract Type: Oral
Abstract Category : Stars, ISM and Galaxy
Abstract : Discoveries of stellar-mass black holes (BHs) via X-ray, radio, and gravitational waves, combined with binary stellar evolution theory indicate that BHs with detached luminous companions (LCs) should be found in large numbers in the Milky Way (MW). We simulate highly realistic models of BH--LC binaries in the MW the binary-population synthesis code COSMIC. We find that Gaia can discover a few hundreds of detached BH--LC binaries by monitoring the motions of the LCs during its 10-year observation. Proper motion, parallax, and magnitude of the LCs would also be known from Gaia data, hence, LC properties, such as mass, luminosity, age, and metallicity can be determined relatively easily. Gaia’s astrometry alone can confirm the nature of the unseen primary by constraining its mass, M_BH>3M☉. Follow-up radial velocity and X-ray observations are expected to improve the constraints on the BH mass and BH--LC for these candidates discovered by Gaia. If found, these BHs will be the first where their mass as well as the metallicity and age of their progenitors will be known almost model-independently. In my talk, I will share our exciting key results.