SCYON Abstract

Received on October 15 2006

Star Clusters with Primordial Binaries: III. Dynamical Interaction between Binaries and an Intermediate Mass Black Hole

AuthorsMichele Trenti (1,2), Eliani Ardi (1), Shin Mineshige (1), and Piet Hut (3)
Affiliation
(1) Yukawa Institute for Theoretical Physics, Kyoto, J
(2) Space Telescope Science Institute, Baltimore, MD
(3) Institute for Advanced Study, Princeton, NJ
Accepted byMonthly Notices of the Royal Astronomical Society
Contacttrenti@stsci.edu
URLhttp://www.arxiv.org/abs/astro-ph/0610342
Links

Abstract

We present the first study of the dynamical evolution of an isolated star cluster that combines a significant population of primordial binaries with the presence of a central black hole. We use equal-mass direct N-body simulations, with N ranging from 4096 to 16384 and a primordial binary ratio of 0-10%; the black hole mass is about one percent of the total mass of the cluster. The evolution of the binary population is strongly influenced by the presence of the black hole, which gives the cluster a large core with a central density cusp. Starting from a variety of initial conditions (Plummer and King models), we first encounter a phase, that last approximately 10 half-mass relaxation times, in which binaries are disrupted faster compared to analogous simulations without a black hole. Subsequently, however, binary disruption slows down significantly, due to the large core size. The dynamical interplay between the primordial binaries and the black hole thus introduces new features with respect to the scenarios investigated so far, where the influence of the black hole and of the binaries have been considered separately. A large core to half mass radius ratio appears to be a promising indirect evidence for the presence of a intermediate-mass black hole in old globular clusters.