Constraints on compact dark matter from gravitational wave microlensing
  If a significant fraction of dark matter is in the form of compact objects,
they will cause microlensing effects in the gravitational wave (GW) signals
observable by LIGO and Virgo. From the non-observation of microlensing
signatures in the binary black hole events from the first two observing runs
and the first half of the third observing run, we constrain the fraction of
compact dark matter in the mass range $10^2-10^5~{M_\odot}$ to be less than
$\simeq 50-80\%$ (details depend on the assumed source population properties
and the Bayesian priors). These modest constraints will be significantly
improved in the next few years with the expected detection of thousands of
binary black hole events, providing a new avenue to probe the nature of dark
matter.
