The formation of the first globular clusters in dwarf galaxies before the epoch of reionization

We explore a mechanism for the formation of the first globular clusters, operating during the assembly of dwarf galaxies at high redshifts, z greater than or similar to 10. The substructure in the dark matter and the corresponding potential wells are responsible for setting the cluster scale of 10 5 M. The second mass scale in the formation problem, the stellar scale of similar to1 M., is determined in turn by the processes that cool the gas. We address the origin of the first, cluster mass scale by means of three-dimensional numerical simulations of the collapsing dark matter and gaseous components. We find that the gas falls into the deepest dark subhalos, resulting in a system of approximately five protoglobular clouds. The incipient globular clusters lose their individual dark halos in the process of violent relaxation, leading to the buildup of the general dark halo around the dwarf galaxy.