Constraints on Primordial Black Holes from $N$-body simulations of the Eridanus II Stellar Cluster

Abstract

The evolution of old, compact stellar structures provides strong constraints on macroscopic dark matter candidates such as primordial black holes. In view of recent observational data for the Eridanus II dwarf galaxy, we perform the first $N$-body simulations of its central stellar cluster to model dynamical heating by PBHs. We find evidence that such candidates must be lighter than about one solar mass if they constitute the totality of the dark matter. We additionally derive constraints on the fraction of the dark matter in macroscopic objects as a function of mass, by modeling the remainder of the dark matter as standard, fluid-like cold dark matter.