# LISA Detection of Binary Black Holes in the Milky Way Galaxy

## TL;DR

This paper estimates the number of tightly bound binary black holes in the Milky Way and discusses their potential detection by LISA, including possible X-ray signatures, based on merger rates from LIGO.

## Contribution

It provides the first estimate of the abundance of close binary black holes in the Milky Way and assesses their detectability with LISA.

## Key findings

- LISA could detect binary black holes in the Milky Way.
- Tightly bound binaries likely originate from larger separations.
- Possible X-ray signatures of such binaries are identified.

## Abstract

Using the black hole merger rate inferred from LIGO, we calculate the abundance of tightly bound binary black holes in the Milky Way galaxy. Binaries with a small semimajor axis ($\lesssim 10 R_\odot$) originate at larger separations through conventional formation mechanisms and evolve as a result of gravitational wave emission. We find that LISA could detect them in the Milky Way. We also identify possible X-ray signatures of such binaries.