The collapse of dense star clusters to supermassive black holes - Binaries and gravitational radiation

Abstract

The formation of binaries as a result of normal stellar-dynamic processes in dense clusters of compact stars is investigated analytically. The results of numerical simulations based on a simple homological model for the evolution of a cluster up to the point of catastrophic collapse are presented in extensive graphs and characterized in detail. It is shown that gravitational radiation begins to have a significant effect long before the onset of the high-redshift state. In the later stages, radiative dissipation from binary captures and flyby orbits acts to increase the final core mass that can undergo catastrophic collapse. Realistic initial conditions are found to lead to final cores of 100-100,000 solar masses, which can then collapse in a few dynamical time scales to form black holes 10-150 times larger. It is suggested that gravitational radiation from compact-star binaries may be detectable by ground-based interferometers. 55 references.