arXiv subjects

Masum Murshid

Publications and source records attributed to Masum Murshid.

6 recordsLinked to original sources

arXiv2026

Influence of Fermionic Dark Matter on the Structural and Tidal Properties of Neutron Stars

We investigate the influence of ideal Fermi gas dark matter on the observable properties of neutron stars (NSs). Our analysis considers dark matter (DM) particle masses ($μ$) ranging from $0.2$ GeV to $1$ GeV and various DM mass fractions ($f$). By examining the coexistence of DM and baryonic matter (BM), we explore the formation of either a dense DM core or an extended dark halo within NSs. Our findings indicate that the resulting DM distribution depends critically on both $μ$ and $f$. We systematically explore the parameter space of the fermionic DM model using two representative BM equations of state (EoSs) by applying constraints from NS radius measurements by the Neutron Star Interior Composition Explorer (NICER), observations of $2M_{\odot}$ NSs, and tidal deformability limits from the LIGO/Virgo Collaboration. This comprehensive analysis enables us to exclude specific ranges of $μ$ and $f$, demonstrating that the amount of accumulated DM must be relatively small to satisfy current astrophysical constraints.

gr-qc↗

arXiv2025

Braneworld Neutron Stars: Constraining Brane Tension with Observational Data

In this article, we investigate the properties of neutron stars within the braneworld model, employing six distinct piece-wise polytropic equation of states. These equation of states satisfy observational constraints put by GW170817 event and pulsar observations (PSR J0740 and PSR J0030) within general relativity framework. Our primary goal is to assess whether these equation of states, in conjunction with the braneworld framework, can accommodate more massive neutron stars, as suggested by the GW190814 observation, while remaining consistent with established observational constraints. The brane tension parameter significantly affects the mass-radius and mass-tidal deformability relations, particularly for neutron stars with masses exceeding the canonical value. We establish strong constraints on the brane tension by comparing the canonical neutron star radius and tidal deformability with the results from the braneworld model, a stringent lower bound on the brane tension, $λ> 2 \times 10^ {37} \, \text {dyne/cm} ^2 $. Our results demonstrate that the braneworld model allows for the existence of neutron stars with masses greater than those predicted by General Relativity, in agreement with the GW190814 observation, and highlight the significant role of brane tension in shaping the properties of neutron stars.

gr-qc↗

arXiv2024

Neutron Stars In $f(R,T)$ Theory: Slow Rotation Approximation

In this paper, we study the slowly rotating neutron stars in $f(R, T)$ gravity based on Hartle-Thorne formalism. We first consider the simplest matter-geometry coupled modified gravity, namely $f(R, T)=R+2χT$. We compute the mass, radius, moment of inertia, change in radius, and binding energy due to rotation, eccentricity, quadrupole moment, and the tidal love number. The quantities, which are of the second order in angular velocity, like change in radius and binding energy due to rotation, eccentricity, and quadrupole moment, deviate more from their corresponding general relativistic counterparts in lighter neutron stars than heavier ones. Whereas the moment of inertia, which is of the first order in angular velocity, in $f(R, T)=R+2χT$ modified gravity, barely diverges from the general relativistic one. The Equation of state-independent I-Love-Q relation retains in this $f(R, T) $ modified gravity, and it coincides with the general relativistic ones within less than one percent even for the maximum allowed coupling parameters. We also study the slowly rotating neutron star in $f(R, T)=R+αR^{2}+2χT$ up to first order their angular velocity. We calculate the mass, radius, and moment of inertia of neutron stars in this modified gravity. The results show that the impact of the matter-geometric coupling parameter is greater on lighter neutron stars in both of these modified gravity models.

gr-qc↗

arXiv2022

Quasi Normal Modes of Ayon-Beato Garcia Regular Black Holes For Scalar Field

In this paper, we compute quasi-normal modes of ABG black holes (which has a non-linear electrodynamical source) using the WKB methods and AIM. A comparison between the spectrum of QNMs calculated by both methods is made. We analyse how the spectrum of QNMs depends on the black hole parameters, multipole number and overtone number and establish that the ABG black hole is stable against the scalar field.

gr-qc↗

arXiv2021

Analytical model on mass limit of strange stars

In this paper, we present a new kind of stellar model using the Nariai IV metric. This model can be used to study the strange/quark stars(which is our present interest, though it can also be applicable to neutron stars). We present a mass-radius region where all the regularity conditions, energy conditions, the TOV equation, and stability conditions are satisfied. According to our model, strange stars having mass up to $1.9165M_{\odot}(=2.81 km)$ is stable. A strange star having a mass greater than $1.9165M_{\odot}$ violates the stability conditions. This model can be very useful to predict the radius of strange stars of mass greater than $1 M_{\odot}$.

gr-qc↗

arXiv2021

Analytical model of low mass strange stars in 2+1 spacetime

The low mass compact stars are quite fascinating objects to study for their enigmatic behaviour. In this paper, we have modeled this kind of low mass strange stars based on the Heintzmann ansatz (H. Heintzmann., Zeitschrift für Physik, vol.228, 489, 1969.) in $(2+1)$ dimension. Attractive anisotropic force plays a significant role to restrict the upper mass limit (which is comparatively low) of the strange star. We have applied our model to some low mass strange stars. Our model could be useful to predict the important parameters of the low mass strange stars.

gr-qc↗