Merger rate of black hole binaries from globular clusters: theoretical error bars and comparison to gravitational wave data from GWTC-2

Understand

Black hole binaries formed dynamically in globular clusters are believed to be one of the main sources of gravitational waves in the Universe.

• Here, we use our new population synthesis code, cBHBd, to determine the redshift evolution of the merger rate density and masses of black hole binaries formed in globular clusters.
• We simulate $\sim 2$ million models to explore the parameter space that is relevant to real clusters and over all mass scales.
• We show that when uncertainties on the initial cluster mass function and density are properly taken into account, they become the two dominant factors in setting the theoretical error bars on merger rates.