Dynamical Formation of the GW150914 Binary Black Hole

TL;DR

This paper investigates how dense star clusters can dynamically form binary black holes like GW150914, showing that such environments are likely sources of these mergers and are consistent with observed rates.

Contribution

It demonstrates that globular clusters with specific masses can efficiently produce GW150914-like black hole mergers through dynamical interactions.

Findings

Globular clusters of $3\times10^5$ to $6\times10^5 M_{\odot}$ are optimal for forming GW150914-like binaries.

Dynamical processes in clusters can account for observed binary black hole merger rates.

Detection of GW150914 aligns with predictions from globular cluster models.

Abstract

We explore the possibility that GW150914, the binary black hole merger recently detected by Advanced LIGO, was formed by gravitational interactions in the core of a dense star cluster. Using models of globular clusters with detailed $N$-body dynamics and stellar evolution, we show that a typical cluster with a mass of $3\times10^5M_{\odot}$ to $6\times10^5M_{\odot}$ is optimal for forming GW150914-like binary black holes that will merge in the local universe. We identify the most likely dynamical processes for forming GW150914 in such a cluster, and we show that the detection of GW150914 is consistent with the masses and merger rates expected for binary black hole mergers from globular clusters. Our results show that dynamical processes provide a significant and well-understood pathway for forming binary black hole mergers in the local universe. Understanding the contribution of dynamics to the binary black hole merger problem is a critical step in unlocking the full potential of gravitational-wave astronomy.