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

TL;DR

This study uses N-body simulations of the Eridanus II stellar cluster to place new constraints on primordial black holes as dark matter candidates, suggesting they must be lighter than about one solar mass if they make up all dark matter.

Contribution

First N-body simulations of the Eridanus II cluster to model dynamical heating effects from primordial black holes, providing novel constraints on their mass and abundance.

Findings

Primordial black holes must be lighter than about one solar mass if they constitute all dark matter.

Constraints on the fraction of dark matter in primordial black holes as a function of their mass.

Modeling of the remaining dark matter as cold, fluid-like matter.

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.