No abstract

We explore the presence of self-interacting bosonic dark matter (DM) whithin neutron stars (NSs) in light of the latest mass-radius measurements of the Neutron Star Interior Composition Explorer (NICER). The bosonic DM is distributed in NSs as a core for DM particles with high mass, low fraction and low self-coupling constant or as a halo for particles with low mass, high fraction and high self-coupling constant leading to formation of DM admixed NSs. We focus on the evolution of the visible and dark radius of the mixed object due to DM model parameters and fractions. It is shown that DM core formation reduces the visible radius and total mass pushing them below observational limits while halo formation is in favor of the latest mass-radius constraints. Applying joint constraints for radius of 1.4M NSs and the maximum mass from NICER and LIGO/Virgo observations, we scan over the parameter space of the bosonic DM model to obtain an allowed region. It turns out that the maximum mass limit provides a more stringent constraint compare to the radius one. Our investigation allows for the exclusion of a large portion of DM fractions for sub-GeV bosons and limited the amount of accumulated DM to be less than ∼ 4% for the entire mass range at the strong coupling regime λ = π. In this paper, we introduce main features of the pulse profile corresponding to the DM admixed NS and the effect of DM halo on the light bending is considered extensively as an independent probe for the DM model. We find that the depth of minimum fluxes in the pulse profiles crucially depend on the amount of DM distributed around NS and its compactness. The current/future astrophysics missions via precise measurements of compact object properties may test the possibility of the existence of DM within NSs and break the degeneracies between different scenarios to interpret exotic observations.

No abstract

The concept of boson stars (BSs) was first introduced by Kaup and Ruffini-Bonazzola in the 1960s. Following this idea, we investigate an effect of self-interacting asymmetric bosonic dark matter (DM) according to Colpi et al. model for BSs (1986) on different observable properties of neutron stars (NSs). In this paper, the bosonic DM and baryonic matter (BM) are mixed together and interact only through gravitational force. The presence of DM as a core of a compact star or as an extended halo around it is examined by applying different boson masses and DM fractions for a fixed coupling constant. The impact of DM core/halo formations on a DM admixed NS properties is probed through the maximum mass and tidal deformability of NSs. Thanks to the recent detection of Gravitational-Waves (GWs) and the latest X-ray observations, the DM admixed NS's features are compared to LIGO/Virgo and NICER results.