Presence of bosonic dark matter in admixed neutron stars

Abstract

We study how the presence of bosonic self-interacting dark matter influences the properties of admixed neutron stars. We only consider the gravitational interaction between baryonic and dark matter. We also explore different possibilities for the unknown mass, mχ, and self-coupling, λ, of the dark matter component, as well as different ratios of the central energy densities of dark and baryonic matter, ϵc D/ϵc B. Two scenarios are found: for mχ = 400 MeV, the dark matter is contained in the core of the star, which decreases its mass and radius with increasing dark matter fraction, whereas an extended halo of dark matter is formed for mχ = 100 MeV. The tidal deformability obtained from the gravitational waves of a binary neutron star merger favors the dark matter core scenario and puts severe constraints on the self-coupling value