SCYON Abstract

Received on September 6 2012

Understanding the Dynamical State of Globular Clusters: Core-Collapsed vs Non Core-Collapsed

Authors	Sourav Chatterjee, Stefan Umbreit, John M. Fregeau, and Frederic A. Rasio
Affiliation	Department of Astronomy, University of Florida, Gainesville, 32611 Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Dept. of Physics & Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA, Institute for Defense Analyses, 4850 Mark Center Dr, Alexandria, VA 22311, Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Dept. of Physics & Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA
Submitted to	Monthly Notices of the Royal Astronomical Society
Contact	s.chatterjee@astro.ufl.edu
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Abstract

We study the dynamical evolution of globular clusters using our Hénon-type Monte Carlo code for stellar dynamics including all relevant physics such as two-body relaxation, single and binary stellar evolution, Galactic tidal stripping, and strong interactions such as physical collisions and binary mediated scattering. We compute a large database of several hundred models starting from broad ranges of initial conditions guided by observations of young and massive star clusters. We show that these initial conditions very naturally lead to present day clusters with properties including the central density, core radius, half-light radius, and cluster mass, that match well with those of the old Galactic globular clusters. In particular, we can naturally reproduce the bimodal distribution in observed core radii separating the ``core-collapsed" vs the ``non core-collapsed" clusters. We see that the core-collapsed clusters are those that have reached or are about to reach the equilibrium ``binary burning" phase. The non core collapsed clusters are still undergoing gravo-thermal contraction.