The clustering of massive Primordial Black Holes as Dark Matter: measuring their mass distribution with Advanced LIGO

TL;DR

This paper explores how Advanced LIGO can measure the mass distribution and clustering of massive primordial black holes, which could constitute dark matter, and discusses their implications for galaxy formation and cosmology.

Contribution

It demonstrates the potential of gravitational wave observations to determine the mass distribution and clustering of primordial black holes as dark matter candidates.

Findings

Merging rates of PBHs could match LIGO observations if PBHs are clustered like dwarf galaxies.

Massive PBHs could explain the missing satellite and too-big-to-fail problems.

Future GW detectors can measure PBH abundance and mass distribution with 10% accuracy.

Abstract

The recent detection by Advanced LIGO of gravitational waves (GW) from the merging of a binary black hole system sets new limits on the merging rates of massive primordial black holes (PBH) that could be a significant fraction or even the totality of the dark matter in the Universe. aLIGO opens the way to the determination of the distribution and clustering of such massive PBH. If PBH clusters have a similar density to the one observed in ultra-faint dwarf galaxies, we find merging rates comparable to aLIGO expectations. Massive PBH dark matter predicts the existence of thousands of those dwarf galaxies where star formation is unlikely because of gas accretion onto PBH, which would possibly provide a solution to the missing satellite and too-big-to-fail problems. Finally, we study the possibility of using aLIGO and future GW antennas to measure the abundance and mass distribution of PBH in the range [5 - 200] Msun to 10\% accuracy.