Can a Moderately Massive Black Hole Reverse Core Collapse?

Abstract

Direct N-body simulations show that the heat flux from the cusp of stars surrounding an object of mass M ∿ 10–100 M_⊙ has a profound effect on the evolution of a cluster of N stars of mass m ∿ 1 M_⊙. A cluster containing an object which is ≳5% of its total mass expands, transferring most of the cluster binding energy to a few stars deep in the cusp within several central relaxation times. The results, together with analytic estimates, suggest that core collapse in a globular cluster will be reversed when the core mass is reduced to ∿10 M. As is discussed below, this result does not depend on whether or not stars are disrupted by the black hole.