# Hunting Black Holes with Gaia

## TL;DR

This paper predicts that Gaia will detect approximately 200,000 astrometric binaries with black holes and stellar companions, primarily with longer orbital periods and specific mass ranges, over its five-year mission.

## Contribution

The study provides the first detailed prediction of the number and characteristics of black hole binaries Gaia can detect astrometrically.

## Key findings

- Approximately 200,000 black hole binaries detectable by Gaia.
- Detection favored for systems with longer orbital periods.
- Black hole masses around 6-10 solar masses and companions 1-2 solar masses dominate.

## Abstract

We predict the number of black holes with stellar companions that are potentially detectable with Gaia astrometry over the course of its five-year mission. Our model estimates that nearly 2$\times$10$^5$ astrometric binaries hosting black holes and stellar companions brighter than Gaia's detection threshold, G $\sim$ 20, should be discovered with 5$\sigma$ sensitivity. Among these detectable binaries, systems with longer orbital periods are favored, and black hole and stellar companion masses in the range M$_{BH} \sim$ 6-10 M$_\odot$ and M$_* \sim$ 1-2 M$_\odot$, respectively, are expected to dominate.