arXiv subjects

Padmalaya Dash

Publications and source records attributed to Padmalaya Dash.

3 recordsLinked to original sources

arXiv2025

Investigating the correlations of bulk properties of hyperon star with dark matter

The strong gravitational pull of the neutron star leads to the accretion of dark matter (DM) inside the core of the neutron star. The accretion of DM affects the bulk properties of the neutron star. Here, we study how the accretion of WIMP (Weakly Interacting Massive Particles) dark matter particles affects the $\Delta-$admixed hyperon star's bulk properties specifically mass, radius, tidal deformability, $f-$mode frequency and moment of inertia. The inclusion of dark matter softens the EOS (equation of state) and reduces the maximum possible mass, canonical radius, canonical tidal deformability, and moment of inertia of canonical star. However, the $f-$mode frequency of the canonical star increases. We find a cubical correlation between the dark matter fermi momenta $k_f^{DM}$ and bulk properties of canonical star.

astro-ph.HE↗

arXiv2024

Exploring the impact of $\Delta$-isobars on Neutron Star

We include the $\Delta$-isobars in the equation of state (EOS) of neutron star (NS) and study its effects with various parameter sets of the RMF model. We compare our results with the NS's constraints from the mass-radius measurement of PSR J0348+0432, PSR J1614-2230, PSR J0030+0451, PSR J0740+6620, PSR J0952-0607, and tidal deformability of GW170817. We calculate the mass-radius profile and tidal deformabilities of the NS using 21 parameter sets of the RMF model.Analyzing the result with various parameters, it is clear that only few parameter sets can satisfy simultaneously the constraints from NICER and GW170817. NLD parameter set satisfy all the constraints of NICER and GW170817. For its strong predictive power for the bulk properties of the neutron star, we take NLD parameter set as a representative for the detailed calculation of effect of $\Delta$-isobar on neutron star properties. We demonstrate that it is possible that $\Delta$-isobar can produce at 2-3 times the saturation density by adjusting the coupling constants $X_{\sigma\Delta}$, $X_{\rho\Delta}$ and $X_{\omega\Delta}$ in an appropriate range. Bulk properties of the NS like mass-radius profile and tidal deformability is strongly affected by the interaction strength of $\Delta$-isobar. Our calculation shows that it is also possible that by choosing $X_{\sigma\Delta}$, $X_{\rho\Delta}$ and $X_{\omega\Delta}$ to a suitable range the threshold density of $\Delta^-$-isobar become lower than $\Lambda^0$ hyperon. For a particular value of $\Delta$-coupling constants, the $R_{1.4}$ decrease by 1.7 km. This manuscipt give an argumentative justification for allowing $\Delta$-isobar degrees of freedom in the calculation of the NS properties.

nucl-th↗

arXiv2020

Correlation between the curvature and some properties of the neutron star

According to the general theory of relativity, a massive body induces curvature in the surrounding spacetime. In this study, the surface curvature (SC) of neutron stars is computed using various curvature quantities derived from the relativistic mean-field, density-dependent RMF, and Skyrme-Hartree-Fock equations of states. Neutron star properties, including mass, radius, compactness, and central density, are calculated utilizing the Tolman-Oppenheimer-Volkoff equations. The analysis reveals a significant cubic correlation between the SC and compactness for the canonical 1.4 $M_{\odot}$ neutron star, with a correlation coefficient of 0.99, indicating an almost linear relationship. A similarly significant inverse cubic correlation is observed between the SC and the radius of the canonical star. However, these correlations diminish for the maximum mass NS. Furthermore, a universal relation between the SC and the dimensionless tidal deformability ($\Lambda$) for the canonical neutron star is established. Using the tidal deformability constraint of GW170817 ($\Lambda_{1.4} = 190_{-120}^{+390}$), the surface curvature is limited to SC$_{1.4} (10^{14}) = 2.87^{+0.30}_{-0.78}$ at a confidence level 90\%. Furthermore, the tidal deformability constraint of the secondary component in the GW190814 event ($\Lambda_{1.4} = 616_{-158}^{+273}$) offers a more stringent limit, with the result of SC$_{1.4} (10^{14}) = 2.03^{+0.27}_{-0.36}$. These findings indicate that the GW190814 event imposes more rigorous constraints on SC compared to GW170817.

astro-ph.HE↗