Analyzing Fermionic Dark Matter Scenarios with Anomalous Compact Objects

Abstract In this paper, we consider three compact objects (HESS J1731-347, PSR J1231-1411, XTE J1814-338) with anomalous mass–radius relations to analyze the possibility of their being dark matter admixed neutron stars. We try to infer the properties of the dark matter particles, under the assumption of their behaving as a free Fermi gas. The main novelty relies on the use of a baryonic equation of state obtained from first principles over the whole density range, which allows the model dependence of the baryonic part of the calculation to be eliminated. Once the possible dark matter admixed neutron star configurations are obtained, we check their stability and whether it is feasible for a neutron star to capture the necessary dark matter fraction. Our analysis shows that our dark matter model favours the dark matter admixed neutron star hypothesis over the pure baryonic neutron star one, with the most favoured dark matter mass of m DM = 1 GeV, although the necessary dark matter content cannot be explained in a standard galactic environment.