Microlensing and dynamical constraints on primordial black hole dark matter with an extended mass function

TL;DR

This paper reevaluates microlensing and dynamical constraints on primordial black hole dark matter with extended mass functions, finding conflicting constraints that challenge the viability of PBHs as all dark matter.

Contribution

It provides a detailed recalculation of constraints for extended PBH mass functions, revealing conflicts that limit their role as dark matter.

Findings

Microlensing and dynamical constraints conflict for extended mass functions.

No single mass function satisfies both microlensing and dynamical constraints.

Constraints challenge the hypothesis that PBHs constitute all dark matter.

Abstract

The recent discovery of gravitational waves from mergers of $\sim 10 \, M_{\odot}$ black hole binaries has stimulated interested in Primordial Black Hole dark matter in this mass range. Microlensing and dynamical constraints exclude all of the dark matter being in compact objects with a delta function mass function in the range $10^{-7} \lesssim M/ M_{\odot} \lesssim 10^{5}$. However it has been argued that all of the dark matter could be composed of compact objects in this range with an extended mass function. We explicitly recalculate the microlensing and dynamical constraints for compact objects with an extended mass function which replicates the PBH mass function produced by inflation models. We find that the microlensing and dynamical constraints place conflicting constraints on the width of the mass function, and do not find a mass function which satisfies both constraints.