Gravitational wave microlensing by dressed primordial black holes
Juan Urrutia, Ville Vaskonen, Hardi Veermäe
Abstract
We study gravitational wave microlensing by primordial black holes (PBHs), accounting for the effect of a particle dark matter minihalo surrounding them. Such minihaloes are expected when PBHs make up only a fraction of all dark matter. We find that current LIGO-Virgo detections disfavor dark matter in the form of PBHs heavier than $100{M}_{\ensuremath{\bigodot}}$ at $1.4\ensuremath{\sigma}$. The next generation observatories can potentially probe PBHs as light as $0.01{M}_{\ensuremath{\bigodot}}$ and down to $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ fraction of all dark matter. We also show that these detectors can distinguish between dressed and naked PBHs, providing a novel way to study the distribution of particle dark matter around black holes and potentially shed light on the origins of black holes.