Understand
There is significant observational evidence that a large fraction of galactic centers, including those in the Milky Way and M31, host a supermassive black hole (SMBH) embedded in a triaxial nuclear star cluster.
- In this work, we study the secular orbital evolution of binaries in these environments, and characterize the regions and morphological properties of nuclear star clusters that lead to gravitational wave mergers and/or tidal captures.
- We show that even a modest level of triaxiality in the density distribution of a cluster (an ellipsoid with axis ratios of 0.7 and 0.95) dramatically enhances the merger rates in the central parsecs of the Galaxy by a factor of up to ~10-30 relative to a spherical density distribution.
- Moreover, we show that the merger fraction of binaries with semi-major axes in the range 10-100 AU remains above 10% for the entire central parsec of the cluster, reaching values close to unity at a distance of ~0.2-0.4 pc from the SMBH.