Primordial Black Holes as a dark matter candidate

Abstract

Primordial Black Holes (PBHs) are black holes formed in the early Universe, for instance from the collapse of large density perturbations generated by inflation. The discovery of gravitational waves from mergers of ~10 Solar mass black hole binaries has led to increased interest in PBHs as a dark matter candidate. I will review the formation of PBHs and the limits on their abundance. I will also emphasize key open questions in the field (e.g. the probability distribution of the density perturbations from which PBH form, clustering, and methods for constraining asteroid mass PBHs).