Prospects for probing gravitational waves from primordial black hole binaries

TL;DR

Future gravitational wave detectors could significantly improve constraints on primordial black hole binaries across a wide mass range, potentially confirming their role in explaining certain microlensing events.

Contribution

This paper demonstrates the enhanced sensitivity of upcoming GW detectors in probing primordial black hole binaries from asteroid to supermassive scales, including novel detection methods.

Findings

Galactic PBH binaries as low as 10^{-5}M_\odot can be detected with future GW observatories.

Future detectors can test the PBH hypothesis for ultrashort microlensing events.

Potential to observe GWs from asteroid mass PBHs via graviton-photon conversion.

Abstract

We study the prospects of future gravitational wave (GW) detectors in probing primordial black hole (PBH) binaries. We show that across a broad mass range from $10^{-5}M_\odot$ to $10^7M_\odot$, future GW interferometers provide a potential probe of the PBH abundance that is more sensitive than any currently existing experiment. In particular, we find that galactic PBH binaries with masses as low as $10^{-5}M_\odot$ may be probed with ET, AEDGE and LISA by searching for nearly monochromatic continuous GW signals. Such searches could independently test the PBH interpretation of the ultrashort microlensing events observed by OGLE. We also consider the possibility of observing GWs from asteroid mass PBH binaries through graviton-photon conversion.