Investigating dark matter-admixed neutron stars with NITR equation of state in light of PSR J0952-0607

Abstract

The fastest and heaviest pulsar, PSR J0952-0607, with a mass of M = 2.35±0.17 M ⊙, has recently been discovered in the disk of the Milky Way Galaxy. In response to this discovery, a new RMF model, 'NITR' has been developed. The NITR model's naturalness has been confirmed by assessing its validity for various finite nuclei and nuclear matter properties, including incompressibility, symmetry energy, and slope parameter values of 225.11, 31.69, and 43.86 MeV, respectively. These values satisfy the empirical/experimental limits currently available. The maximum mass and canonical radius of a neutron star (NS) calculated using the NITR model parameters are 2.355 M ⊙ and 13.13 km, respectively, which fall within the range of PSR J0952-0607 and the latest NICER limit. This study aims to test the consistency of the NITR model by applying it to various systems. As a result, its validity is extensively calibrated, and all the nuclear matter and NS properties of the NITR model are compared with two established models such as IOPB-I and FSUGarnet. In addition, the NITR model equation of state (EOS) is employed to obtain the properties of a dark matter admixed NS (DMANS) using two approaches (I) single-fluid and (II) two-fluid approaches. In both cases, the EOS becomes softer due to DM interactions, which reduces various macroscopic properties such as maximum mass, radius, tidal deformability, etc. The various observational data such as NICER and HESS are used to constrain the amount of DM in both cases. Moreover, we discuss the impact of dark matter (DM) on the nonradial f-mode frequency of the NS in a single fluid case only and try to constrain the amount of DM using different theoretical limits available in the literature.