SCYON Abstract

Received on March 6 2001

Halo enrichment by disrupted globular clusters

AuthorsH. Baumgardt
AffiliationDept. of Mathematics and Statistics, University of Edinburgh, Edinburgh EH9 3JZ, UK
To appear in Modes of Star Formation, ASP Conference Series, Eds. Eva Grebel & Wolfgang Brandner


We study the evolution of the galactic globular cluster system to determine its initial mass-function and the fraction of halo stars that could have come from disrupted globular clusters. We study the cluster evolution under the influence of two destruction mechanisms: Two-body relaxation and dynamical friction. New results of N-body simulations are used for the lifetimes of clusters dissolving under the influence of two-body relaxation. Two different mass-functions are studied: A gaussian initial distribution in log(MC) with mean mass and scatter similar to what one observes for the galactic globular cluster system, and a power-law distribution resembling what is seen for clusters in merging and interacting galaxies. We find that in the inner parts of the galaxy, both distributions evolve in such a way that they are consistent with the observations. In the outer parts, a gaussian initial distribution gives the better fit. This might change however if elliptic orbits are considered, or there are undiscovered low-mass clusters in the galactic halo. In any case, only a small fraction of the stellar halo of the Milky Way originated in globular clusters.