Inverting the dynamical evolution of globular clusters: clues to their origin
Abstract
Scaling relations for globular clusters (GC) differ from scaling relations for pressure supported (elliptical) galaxies. We show that two-body relaxation is the dominant mechanism in shaping the bivariate dependence of density on mass and Galactocentric distance for Milky Way GCs with masses <10^6 Msun, and it is possible, but not required, that GCs formed with similar scaling relations as ultra-compact dwarf galaxies. We use a fast cluster evolution model to fit a parameterised model for the initial properties of Milky Way GCs to the observed present-day properties. The best-fit cluster initial mass function is substantially flatter (power-law index alpha =- 0.6+/-0.2) than what is observed for young massive clusters (YMCs) forming in the nearby Universe (alpha =~-2). A slightly steeper CIMF is allowed when considering the metal-rich GCs separately (alpha =~-1.2+/-0.4$). If stellar mass loss and two-body relaxation in the Milky Way tidal field are the dominant disruption mechanisms, then GCs formed differently from YMCs.
Cite
@article{arxiv.1512.01487,
title = {Inverting the dynamical evolution of globular clusters: clues to their origin},
author = {Mark Gieles and Poul Alexander},
journal= {arXiv preprint arXiv:1512.01487},
year = {2015}
}
Comments
8 pages, 5 figures, invited review for IAUS 316, "Formation, evolution, and survival of massive star clusters", eds. C. Charbonnel & A. Nota