Intermediate mass black holes' effect on compact object binaries

TL;DR

This study uses N-body simulations to show that intermediate mass black holes can significantly influence the dynamics and merger rates of stellar-mass black hole binaries near galactic centers, providing potential observational constraints.

Contribution

It demonstrates how IMBHs affect binary evaporation and merger probabilities, highlighting their role in galactic nucleus dynamics.

Findings

IMBHs increase binary evaporation rates.

IMBHs can cause 1-6% of binaries to merge.

Observations can constrain IMBH populations.

Abstract

Although their existence is not yet confirmed observationally, intermediate mass black holes (IMBHs) may play a key role in the dynamics of galactic nuclei. In this paper, we neglect the effect of the nuclear star cluster itself and investigate only how a small reservoir of IMBHs influences the secular dynamics of stellar-mass black hole binaries, using N-body simulations. We show that our simplifications are valid and that the IMBHs significantly enhance binary evaporation by pushing the binaries into the Hill-unstable region of parameter space, where they are separated by the SMBH's tidal field. For binaries in the S-cluster region of the Milky Way, IMBHs drive the binaries to merge in up to 1-6% of cases, assuming five IMBHs within 5 pc of mass 10,000 solar masses each. Observations of binaries in the Galactic center may strongly constrain the population of IMBHs therein.