Radial oscillations of dark matter admixed neutron stars

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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.

“…In the single-fluid model, DM particles interact with baryons by exchanging standard model Higgs. The structure of the interacting Lagrangian can be deduced as [21,23,[39][40][41][42]:…”

Section: Single Fluid Dark Matter (Sfdm) Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Routaray,

Mohanty,

Das

et al. 2023

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“…the dimensionless tidal deformability (Λ) and the non-radial f -mode oscillations. Radial oscillations in NSs for different matter compositions has been an active area of study [19,20,[116][117][118][119] with the matter composition being recently extended to include ∆-resonances as well [18]. Through this work we are proceeding further by studying, for the first time, nonradial f -mode oscillations in NSs with ∆-admixed hypernuclear as well as hyperon-free matter.…”

Section: Introductionmentioning

confidence: 99%

“…These oscillations are categorized into two primary types: radial and non-radial, both of which are subjects of active research. Radial oscillations involve expansions and contractions akin to a pulsating motion that helps maintain the star's spherical shape [17][18][19][20][21]. In contrast, non-radial oscillations manifest as asymmetric vibrations centered around the star's core are guided by a restoring force that brings the star back to its equilibrium state [9][10][11][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Probing the impact of delta-baryons on nuclear matter and non-radial oscillations in neutron stars

Kalita,

Routaray,

Ghosh

et al. 2024

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Non-radial oscillations of Neutron Stars (NSs) provide a means to learn important details regarding their interior composition and equation of state. We consider the effects of Δ-baryons on non-radial f-mode oscillations and other NS properties within the Density-Dependent Relativistic Mean Field formalism. Calculations are performed for Δ-admixed NS matter with and without hyperons. Our study of the non-radial f-mode oscillations revealed a distinct increase in frequency due to the addition of the Δ-baryons with upto 20% increase in frequency being seen for canonical NSs. Other bulk properties of NSs, including mass, radii, and dimensionless tidal deformability (Λ) were also affected by these additional baryons. Comparing our results with available observational data from pulsars (NICER) and gravitational waves (LIGO-VIRGO collaboration), we found strong agreement, particularly concerning Λ.

“…Neutron stars (NSs) exhibit oscillations that are regarded as potential sources of GWs, manifesting in various forms including radial [8][9][10][11][12][13] and non-radial [14][15][16][17] modes. When a NS experiences external or internal disturbances, it emits GWs through different oscillation modes known as quasi-normal modes (QNMs), each characterized by the restoring force that brings them back to their equilibrium state.…”

Section: Introductionmentioning

confidence: 99%

The impact of anisotropy on neutron star properties: insights from 𝖨–𝖿–𝖢 universal relations

Mohanty,

Ghosh,

Routaray

et al. 2024

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Anisotropy in pressure within a star emerges from exotic internal processes. In this study, we incorporate pressure anisotropy using the Quasi-Local model. Macroscopic properties, including mass (M), radius (R), compactness (C), dimensionless tidal deformability (Λ), the moment of inertia (I), and oscillation frequency (f), are explored for the anisotropic neutron star. Magnitudes of these properties are notably influenced by anisotropy degree. Universal I–f–C relations for anisotropic stars are explored in this study. The analysis encompasses various EOS types, spanning from relativistic to non-relativistic regimes. Results show the relation becomes robust for positive anisotropy, weakening with negative anisotropy. The distribution of f-mode across M–R parameter space as obtained with the help of C–f relation was analyzed for different anisotropic cases. Using tidal deformability data from GW170817 and GW190814 events, a theoretical limit for canonical f-mode frequency is established for isotropic and anisotropic neutron stars. For isotropic case, canonical f-mode frequency for GW170817 event is f 1.4 = 2.606+0.457 -0.484kHz; for GW190814 event, it is f 1.4 = 2.097+0.124 -0.149kHz. These relationships can serve as reliable tools for constraining nuclear matter EOS when relevant observables are measured.