Pulsar timing can constrain primordial black holes in the LIGO mass window

TL;DR

Pulsar timing has the potential to significantly constrain the abundance of primordial black holes in the 1-30 solar mass range, possibly surpassing existing methods, by detecting subtle gravitational effects on pulsar signals.

Contribution

This study demonstrates that pulsar timing can provide competitive constraints on primordial black holes in the LIGO mass window through non-detection of specific gravitational time delays.

Findings

Future pulsar timing data can constrain PBH density more stringently than current methods.

New pulsars from the Square Kilometre Array could limit PBHs to less than 1-10% of dark matter.

Pulsar timing is a promising tool for probing primordial black holes in the 1-30 solar mass range.

Abstract

The recent discovery of gravitational waves from merging black holes has generated interest in primordial black holes as a possible component of the dark matter. In this paper, we show that pulsar timing may soon have sufficient data to constrain $1$-$1000\,M_{\odot}$ primordial black holes via the non-detection of a third-order Shapiro time delay as the black holes move around the Galactic halo. We present the results of a Monte Carlo simulation which suggests that future data from known pulsars may be capable of constraining the PBH density more stringently than other existing methods in the mass range ~1-30$\,M_{\odot}$. We find that timing new pulsars discovered using the proposed Square Kilometre Array may constrain primordial black holes in this mass range to comprise less than ~1-10% of the dark matter.