Formation of Globular Clusters in Hierarchical Cosmology
Oleg Gnedin
The discoveries of young massive star clusters in starforming
galaxies, brought by the refurbished HST, have led to a paradigm shift
in our understanding of star clusters. The origin of globular
clusters is associated with the regions of active star formation and
is therefore directly linked to the process of galaxy formation. We
use numerical simulations of a Milky Way-sized galaxy to demonstrate
that realistic globular clusters can form naturally at z > 3 in the
concordance LCDM cosmology. The clusters in our model form in the
strongly baryon-dominated cores of supergiant molecular clouds. The
first clusters form at z = 12, while the peak formation appears to be
at z = 3-5. The zero-age mass function of globular clusters can be
approximated by a power-law with the slope -2, in agreement with
observations of young massive star clusters. The total mass of the
cluster population is strongly correlated with the mass of its host
galaxy, as well as with the local average star formation rate. The
first clusters serve as important sources of ionizing radiation within
their host galaxies and may lead to gamma-ray bursts and
intermediate-mass black holes.