2021ApJ...922..242L

We investigate whether the recently observed 2.6 M_☉ compact object in the gravitational wave event GW190814 can be a bosonic dark matter (DM) admixed compact star. By considering the three constraints of mass, radius, and the stability of such an object, we find that if the DM is made of QCD axions, their particle mass m is constrained to a range that has already been ruled out by the independent constraint imposed by the stellar-mass black hole superradiance process. The 2.6 M_☉ object can still be a neutron star admixed with at least 2.0 M_☉ of DM made of axion-like particles (or even a pure axion-like particle star) if 2 x 10^–11 eV <= m <= 2.4 x 10^–11 eV (2.9 x 10^–11 eV <= m <= 3.2 x 10^–11 eV) with a decay constant of f >= 8 x 10¹⁷ GeV.