We study gravitational lensing of gravitational waves from compact object binaries as a probe of compact dark matter (DM) objects such as primordial black holes. Assuming a point mass lens, we perform parameter estimation of lensed gravitational wave signals from compact object binaries to determine the detectability of the lens with ground based laser interferometers. Then, considering binary populations that LIGO-Virgo has been probing, we derive a constraint on the abundance of compact DM from non-observation of lensed events. We find that the LIGO-Virgo observations imply that compact objects heavier than Ml=200M⊙ can not constitute all DM and less than 40% of DM can be in compact objects heavier than Ml=400M⊙. We also show that the DM fraction in compact objects can be probed by LIGO in its final sensitivity for Ml>40M⊙ reaching 2% of the DM abundance at Ml>200M⊙, and by ET for Ml>1M⊙ reaching DM fraction as low as 7×10−5 at Ml>40M⊙.
@article{arxiv.2109.03213,
title = {Lensing of gravitational waves as a probe of compact dark matter},
author = {Juan Urrutia and Ville Vaskonen},
journal= {arXiv preprint arXiv:2109.03213},
year = {2021}
}