Transient Radio Signatures from Neutron Star Encounters with QCD Axion
  Miniclusters
  The QCD axion is expected to form dense structures known as axion
miniclusters if the Peccei-Quinn symmetry is broken after inflation.
Miniclusters that have survived until today will interact with neutron stars
(NSs) in the Milky Way to produce transient radio signals from axion-photon
conversion in the NS magnetosphere. We quantify the properties of these
encounters and find that they occur frequently
($\mathcal{O}(1-100)\,\mathrm{day}^{-1}$); last between a day and a few months;
are spatially clustered towards the Galactic center; and can reach observable
fluxes. These radio transients are within reach of current generation
telescopes and therefore offer a promising pathway to discovering QCD axion
dark matter.
