We propose a model of asymmetric bosonic dark matter (DM) with self-repulsion. By adopting the two-fluids formalism, we study different DM distribution regimes, either, fully condensed inside the core of a star or, otherwise, distributed in a dilute halo around a neutron star (NS). We show that for a given total gravitational mass, DM condensed in a core leads to a smaller radius and tidal deformability compared to a pure baryonic star. This effect may be interpreted as an effective softening of the equation of state (EoS). On the other hand, the presence of a DM halo increases the tidal deformability and total gravitational mass. As a result, an accumulated DM inside compact stars could mimic an apparent stiffening of strongly interacting matter EoS and constraints we impose on it at high densities. Furthermore, from the performed analysis of the effect of DM particles, interaction strength, and relative DM fractions inside NSs we obtained a rigorous constraint on model parameters. Finally, we discuss several smoking gun evidences of the presence of DM that are free from the above mentioned degeneracy between the effect of DM and properties of strongly interacting matter. These signals could be probed with the future and ongoing astrophysical and gravitational wave (GW) surveys.

Organized by: Edoardo Giangrandi