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Related papers: Anisotropic fluid inside a relativistic star

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Within the framework of $f(R,T)$ theories of gravity, we investigate the hydrostatic equilibrium of anisotropic neutron stars with a physically relevant equation of state (EoS) for the radial pressure. In particular, we focus on the $f(R,T)…

General Relativity and Quantum Cosmology · Physics 2023-01-10 Juan M. Z. Pretel

We study gravitational waves from a spinning test particle scattered by a relativistic star using a perturbation method. The present analysis is restricted to axial modes. By calculating the energy spectrum, the waveforms and the total…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Kazuhiro Tominaga , Motoyuki Saijo , Kei-ichi Maeda

An investigation of interior spacetimes sourced by stationary cylindrical anisotropic fluids is presented and specialized to rigidly rotating fluids with an azimuthally directed pressure. Based on the occurence of an extra degree of freedom…

General Relativity and Quantum Cosmology · Physics 2023-08-08 Marie-Noëlle Célérier

In this paper for studying the anisotropic strange quark stars, we assume that the radial pressure inside the anisotropic star is a superposition of pressure in an isotropic case plus a Gaussian perturbation term. Considering a…

Solar and Stellar Astrophysics · Physics 2016-07-26 H. Panahi , R. Monadi , I. Eghdami

In this paper, we study the effects of modification of gravity on the problem of dynamical instability of the spherical relativistic anisotropic interiors. We have considered non-zero influence of expansion scalar throughout during the…

General Relativity and Quantum Cosmology · Physics 2018-07-17 Z. Yousaf , Kazuharu Bamba , M. Z. Bhatti , U. Farwa

We build slowly rotating anisotropic neutron stars using the Hartle-Thorne formalism, employing three distinct anisotropy models--Horvat, Bowers-Liang, and a covariant model--to characterize the relationship between radial and tangential…

High Energy Astrophysical Phenomena · Physics 2025-04-24 L. M. Becerra , E. A. Becerra-Vergara , F. D. Lora-Clavijo

Recently the small value of the cosmological constant and its ability to accelerate the expansion of the Universe is of great interest. We discuss the possibility of forming of anisotropic compact stars from this cosmological constant as…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Sk. Monowar Hossein , Farook Rahaman , Jayanta Naskar , Mehedi Kalam , Saibal Ray

Some theorems for a static prefect fluid sphere, i.e. a star, in the presence of a positive cosmological constant are proved. These theorems put bounds on the pressure profile and internal compactness of the star.

General Relativity and Quantum Cosmology · Physics 2014-02-05 F. Shojai , A. Shojai , M. Mousavi

The gravitational radiation from compact pulsar-like stars depends on the state of dense matter at supranuclear densities, i.e., the nature of pulsar (e.g., either normal neutron stars or quark stars). The solid quark star model is focused…

Astrophysics · Physics 2009-11-13 R. X. Xu

We study relativistic stars in the context of scalar tensor theories of gravity that try to account for the observed cosmic acceleration and satisfy the local gravity constraints via the chameleon mechanism. More specifically, we consider…

General Relativity and Quantum Cosmology · Physics 2015-03-13 E. Babichev , D. Langlois

We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic…

General Relativity and Quantum Cosmology · Physics 2009-11-07 K. H. Lockitch , J. L. Friedman , N. Andersson

We have proposed a model for relativistic compact star with anisotropy and analytically obtained exact spherically symmetric solutions describing the interior of the dense star admitting non-static conformal symmetry. Several features of…

General Relativity and Quantum Cosmology · Physics 2016-04-27 Dibyendu Shee , Farook Rahaman , B. K. Guha , Saibal Ray

We investigate the viscosity driven instability in rotating relativistic stars by means of an iterative approach. We focus on polytropic rotating equilibrium stars and impose an m=2 perturbationin the lapse. We vary both the stiffness of…

Astrophysics · Physics 2007-05-23 Motoyuki Saijo , Eric Gourgoulhon

We develop a simple model for a self-gravitating spherically symmetric relativistic star which begins to collapse from an initially static configuration by dissipating energy in the form of radial heat flow. We utilize the model to show how…

General Relativity and Quantum Cosmology · Physics 2013-12-10 Ranjan Sharma , Shyam Das

We consider the physical conditions of the neutral medium within, and in the environments of, galaxies. The basic physical and morphological properties of the neutral medium within galaxy disks are now quite well-constrained. Systematic…

Astrophysics · Physics 2007-05-23 Robert Braun

Exact solutions for a model with variable $G$, $\Lambda$ and bulk viscosity are obtained. Inflationary solutions with constant (de Sitter-type) and variable energy density are found. An expanding anisotropic universe is found to isotropize…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Arbab I. Arbab

We propose a theoretically consistent modification of gravity in the infrared, which is compatible with all current experimental observations. This is an analog of Higgs mechanism in general relativity, and can be thought of as arising from…

High Energy Physics - Theory · Physics 2009-11-10 Nima Arkani-Hamed , Hsin-Chia Cheng , Markus A. Luty , Shinji Mukohyama

We construct dark energy stars with Chaplygin-type equation of state (EoS) in the presence of anisotropic pressure within the framework of Einstein gravity. From the classification established by Iyer et al. [Class. Quantum Grav. 2, 219…

General Relativity and Quantum Cosmology · Physics 2023-01-18 Juan M. Z. Pretel

We consider perfect fluid bodies ("stars") in general relativity that are axisymmetric, asymptotically flat, and that admit a maximal hypersurface. We show that configurations that extremize the total entropy at fixed ADM mass, ADM angular…

General Relativity and Quantum Cosmology · Physics 2015-09-15 Joshua S. Schiffrin

Current study highlights the physical characteristics of charged anisotropic compact stars by exploring some exact solutions of modified field equations in $f(R,G)$ gravity. A comprehensive analysis is performed from the obtained solutions…

General Relativity and Quantum Cosmology · Physics 2018-06-13 M. Farasat Shamir , Saeeda Zia