Presentation #539.01 in the session “Black Holes and Accretion”.
Studying black hole formation channels enabled by dense environments, such as star clusters, is crucial for understanding the formation of bodies that would otherwise not be possible through isolated stellar evolution. Theoretical evolution models predict a “gap” in the black hole mass spectrum above ~50 solar masses caused by pair-instability supernovae. Here we investigate whether black holes with masses that fall within this “upper mass gap” (similar to the recent LIGO/Virgo event GW190521) can be formed through different formation channels enabled by dense clusters. In particular, we explore the roles of the high mass binary fraction and cluster density and their repercussions on black hole growth. We generate a set of simulations using the CMC (Cluster Monte Carlo) code and study both the evolution of the cluster and the formation and collision histories for the most massive objects that form. We find that almost all simulated clusters with conditions similar to those of the Milky Way form at least one intermediate mass black hole. The results show a strong argument for the formation of massive black holes via dynamical processing as well as binary evolution coalescence in dense clusters.