The authors explore the possibility that the black-hole (BH) binary detected by LIGO could be a signature of dark matter, specifically primordial black holes (PBHs). They consider the scenario where two PBHs in a galactic halo pass close enough to radiate gravitational waves, becoming gravitationally bound and eventually merging. The rate of such mergers is estimated to fall within the range suggested by LIGO for a population of $\sim 30 M_{\odot}$ BHs, which is $2-53 \, \text{Gpc}^{-3} \, \text{yr}^{-1}$. This range overlaps with the rate inferred from the GW150914 event. The authors discuss the uncertainties in these estimates, including the phase-space structure of galactic halos and the concentration-mass relations of halos. They also propose methods to distinguish PBH mergers from traditional astrophysical sources, such as the mass spectrum, high ellipticities, and the stochastic gravitational wave background. The results suggest that next-generation gravitational wave experiments could provide valuable insights into whether LIGO has detected dark matter.The authors explore the possibility that the black-hole (BH) binary detected by LIGO could be a signature of dark matter, specifically primordial black holes (PBHs). They consider the scenario where two PBHs in a galactic halo pass close enough to radiate gravitational waves, becoming gravitationally bound and eventually merging. The rate of such mergers is estimated to fall within the range suggested by LIGO for a population of $\sim 30 M_{\odot}$ BHs, which is $2-53 \, \text{Gpc}^{-3} \, \text{yr}^{-1}$. This range overlaps with the rate inferred from the GW150914 event. The authors discuss the uncertainties in these estimates, including the phase-space structure of galactic halos and the concentration-mass relations of halos. They also propose methods to distinguish PBH mergers from traditional astrophysical sources, such as the mass spectrum, high ellipticities, and the stochastic gravitational wave background. The results suggest that next-generation gravitational wave experiments could provide valuable insights into whether LIGO has detected dark matter.