The Leonard E Parker Center for Gravitation, Cosmology and Astrophysics holds frequent seminars on a broad range of ongoing cosmology and gravitation research topics. Unless otherwise noted, seminars are on Friday afternoons at 1:00 PM in KIRC 2175; there is a gathering for a brown bag lunch at 12:30.

Black hole mergers in nuclear star clusters*
Dr. Fabio Antonini, Northwestern University

Massive stellar clusters are found at the photometric and kinematic centers of most galaxies. Such nuclear clusters are the densest stellar systems observed in the local universe, representing a natural environment where compact object binaries can dynamically form, harden and merge. I will discuss the dynamical processes that lead to the merger of black hole binaries in nuclear clusters in connection to the origin of the binary black hole mergers recently detected by Advanced LIGO. I will show that nuclear clusters can produce a significant population of black hole binaries that merge in the local universe, and that these binaries have clear differences in the statistical distributions of their properties (e.g., mass, eccentricity) when compared to those formed either in globular clusters or through isolated binary evolution. Dynamical processes in nuclear clusters are also found to form very naturally high mass black hole binaries similar to the one that produced GW150914, the first merger signal detected by Advanced LIGO.