# Accreting black hole binaries in globular clusters

**Authors:** Kyle Kremer, Sourav Chatterjee, Carl L. Rodriguez, Frederic A. Rasio  
**arXiv:** [1709.05444](https://arxiv.org/abs/1709.05444)  
**Date:** 2017-09-16  
**Summary page:** https://www.summarizepaper.com/en/paper/1709.05444v1/

## Key points

- The paper explores the formation of mass-transferring binary systems containing black holes within globular clusters.
- Black hole binaries can be formed with main sequence, giant, and white dwarf companions with a variety of orbital parameters in globular clusters spanning a large range in present-day properties.
- These black hole binaries are dynamically created through a median of approximately 30 dynamical encounters within the cluster before and after acquiring the donor.
- The presence of mass-transferring black hole systems has little correlation with the total number of black holes within the cluster at any time due to the net rate of formation of black hole-non-black hole binaries being largely independent from the total number of retained black holes.
- Detecting a mass-transferring black hole binary in a globular cluster does not necessarily indicate that there is a large population of black holes present.
- Studying these accreting binary systems within globular clusters can provide insight into how they interact with other objects within their environment and how they may contribute to gravitational wave signals observed by detectors such as LIGO/Virgo.

## Summary

In their paper "Accreting black hole binaries in globular clusters," Kyle Kremer, Sourav Chatterjee, Carl L. Rodriguez, and Frederic A. Rasio explore the formation of mass-transferring binary systems containing black holes within globular clusters. The authors show that it is possible to form these systems with main sequence, giant, and white dwarf companions with a variety of orbital parameters in globular clusters spanning a large range in present-day properties. These black hole binaries are dynamically created through a median of approximately 30 dynamical encounters within the cluster before and after acquiring the donor. Interestingly, the presence of mass-transferring black hole systems has little correlation with the total number of black holes within the cluster at any time due to the net rate of formation of black hole-non-black hole binaries being largely independent from the total number of retained black holes. Therefore, detecting a mass-transferring black hole binary in a globular cluster does not necessarily indicate that there is a large population of black holes present. The authors' findings have important implications for understanding how these systems form and evolve over time. By studying these accreting binary systems within globular clusters, researchers can gain insight into how they interact with other objects within their environment and how they may contribute to gravitational wave signals observed by detectors such as LIGO/Virgo. Overall, this study sheds light on an important aspect of astrophysics and provides new avenues for future research into these fascinating objects.