A Dynamical Survey of Stellar-mass Black Holes in 50 Milky Way Globular Clusters

Recent numerical simulations of globular clusters (GCs) have shown that stellar-mass black holes (BHs) play a fundamental role in driving cluster evolution and shaping their present-day structure. Rapidly mass-segregating to the center of GCs, BHs act as a dynamical energy source via repeated superelastic scattering, delaying the onset of core collapse and limiting mass segregation for visible stars. While recent discoveries of BH candidates in Galactic and extragalactic GCs have further piqued interest in BH-mediated cluster dynamics, numerical models show that even if significant BH populations remain in today's GCs, they are not typically in directly detectable configurations. We demonstrated in Weatherford et al. that an anticorrelation between a suitable measure of mass segregation in observable stellar populations and the number of retained BHs in GC models can be applied to indirectly probe BH populations in real GCs. Here we estimate the number and total mass of BHs in 50 Milky Way GCs from the Advanced Camera for Surveys GC Survey. For each GC, is measured between observed mainsequence populations and fed into correlations between Δ and BH retention found in our CMC Cluster Catalogs models. We demonstrate that the range in measured from our models matches that for observed GCs to a remarkable degree. Our results constitute the largest sample of GCs for which BH populations have been predicted to date using a self-consistent and robust statistical approach.