Black Holes In Young Stellar Clusters
  We present theoretical models for stellar black hole (BH) properties in
young, massive star clusters. Using a Monte Carlo code for stellar dynamics, we
model realistic star clusters with $N\simeq 5\times10^5$ stars and significant
binary fractions (up to 50%) with self-consistent treatments of stellar
dynamics and stellar evolution. We compute the formation rates and
characteristic properties of single and binary BHs for various representative
ages, cluster parameters, and metallicities. Because of dynamical interactions
and supernova (SN) kicks, more single BHs end up retained in clusters compared
to BHs in binaries. We also find that the ejection of BHs from a cluster is a
strong function of initial density. In low-density clusters (where dynamical
effects are negligible), it is mainly SN kicks that eject BHs from the cluster,
whereas in high-density clusters (initial central density $\rho_c(0) \sim 10^5
\, M_\odot\, {\rm pc}^{-3} $ in our models) the BH ejection rate is enhanced
significantly by dynamics. Dynamical interactions of binary systems in dense
clusters also modify the orbital period and eccentricity distributions while
also increasing the probability of a BH having a more massive companion.
