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Related papers: Isotropic stellar model in mimetic theory

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We investigate various anisotropic spherical distributions of charged celestial bodies within the context of f(R) gravity, where R represents the Ricci scalar. The properties of specific charged compact objects are analyzed by using the…

General Relativity and Quantum Cosmology · Physics 2025-05-13 W. U. Rahman , M. Ilyas , Yi Zhong , De-Liang Yao

In this paper Einstein's field equations, for static spherically symmetric perfect fluid models with a linear barotropic equation of state, are recast into a 3-dimensional regular system of ordinary differential equations on a compact state…

General Relativity and Quantum Cosmology · Physics 2009-10-31 U. S. Nilsson , C. Uggla

We consider spherically symmetric spacetimes sourced by a fluid with pressure anisotropy in the radial direction. We use gauge-invariant perturbation theory to study the stability of this class of spacetimes under axial perturbations. We…

General Relativity and Quantum Cosmology · Physics 2014-07-23 Bhavesh Khamesra , V Suneeta

Isotropic and spatially homogeneous viscous fluid cosmological models are investigated using the truncated Israel-Stewart theory of irreversible thermodynamics to model the bulk viscous pressure. The governing system of differential…

General Relativity and Quantum Cosmology · Physics 2010-04-06 A A Coley , R J van den Hoogen

In the process of protostar formation, astrophysical gas clouds undergo thermodynamically irreversible processes and emit heat and radiation to their surroundings. Due the emission of this energy one can envision an idealized situation in…

General Relativity and Quantum Cosmology · Physics 2016-11-22 Mayer Humi , John Roumas

We study a metric cubic gravity theory considering odd-parity modes of linear inhomogeneous perturbations on a spatially homogeneous Bianchi type I manifold close to the isotropic de Sitter spacetime. We show that in the regime of small…

General Relativity and Quantum Cosmology · Physics 2020-07-20 Masroor C. Pookkillath , Antonio De Felice , Alexei A. Starobinsky

The generalized Gullstrand-Painleve geometry is investigated for expanding matter. Compared to other studies, we take into account an anisotropic stress tensor as the source of curvature with an equation of state resembling the MIT bag…

General Relativity and Quantum Cosmology · Physics 2025-07-01 Hristu Culetu

Much of the published work regarding the Isotropic Singularity is performed under the assumption that the matter source for the cosmological model is a barotropic perfect fluid, or even a perfect fluid with a $\gamma$-law equation of state.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Geoffery Ericksson , Susan M. Scott

The present paper is devoted to investigating the possibility of getting stellar interiors for ultra-dense compact spherical systems portraying an anisotropic matter distribution employing the gravitational decoupling by means of Minimal…

General Relativity and Quantum Cosmology · Physics 2020-03-12 S. K. Maurya , Abdelghani Errehymy , Ksh. Newton Singh , Francisco Tello-Ortiz , Mohammed Daoud

The condition for pressure isotropy is reduced to a recurrence equation with variable, rational coefficients of order three. We prove that this difference equation can be solved in general. Consequently we can find an exact solution to the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 A. J. John , S. D. Maharaj

We complete previous investigations on the thermodynamics of self-gravitating systems by studying the grand canonical, grand microcanonical and isobaric ensembles. We also discuss the stability of polytropic spheres in the light of a…

Astrophysics · Physics 2009-11-07 P. H. Chavanis

In recent years, there have been increasing challenges to the cosmological principle, based on new observations of e.g. supernovae and the cosmic bulk flow. As a result, the cosmological community is speaking their concern for the…

General Relativity and Quantum Cosmology · Physics 2026-05-15 Robbert W. Scholtens , Marcello Seri , Holger Waalkens , Rien van de Weygaert

We construct a toy model for compact stars based on the Finslerian structure of spacetime. By assuming a particular mass function, we find an exact solution of the Finsler-Einstein field equations with an anisotropic matter distribution.…

General Relativity and Quantum Cosmology · Physics 2015-12-01 Farook Rahaman , Nupur Paul , S. S. De , Saibal Ray , Md. Abdul Kayum Jafry

A simple classification is given of the anisotropic relativistic star models, resembling the one of charged isotropic solutions. On the ground of this database, and taking into account the conditions for physically realistic star models, a…

General Relativity and Quantum Cosmology · Physics 2018-01-24 B. V. Ivanov

We analyze dynamical instability of non-static reflection axial stellar structure by taking into account generalized Euler's equation in metric $f(R)$ gravity. Such an equation is obtained by contracting Bianchi identities of usual…

General Relativity and Quantum Cosmology · Physics 2015-12-09 M. Sharif , Z. Yousaf

We present a model of compact astrophysical object under General Theory of Relativity using the anisotropic extension of Tolman IV solution. The anisotropy function, derived from the model, remains well behaved throughout the interior of…

General Relativity and Quantum Cosmology · Physics 2022-06-29 Shyam Das , Bikram Keshari Parida , Koushik Chakraborty , Saibal Ray

We show that the homogeneous, massless Einstein-Vlasov system with toroidal spatial topology and diagonal Bianchi type I symmetry for initial data close to isotropic data isotropizes towards the future and in particular asymptotes to a…

General Relativity and Quantum Cosmology · Physics 2020-02-26 Hamed Barzegar , David Fajman , Gernot Heißel

Modified gravity models have been constantly proposed with the purpose of evading some standard gravity shortcomings. Recently proposed by A.H. Chamseddine and V. Mukhanov, the Mimetic Gravity arises as an optimistic alternative. Our…

General Relativity and Quantum Cosmology · Physics 2018-02-07 D. Momeni , P. H. R. S. Moraes , H. Gholizade , R. Myrzakulov

We consider the three dimensional gravitational Vlasov Poisson system which is a canonical model in astrophysics to describe the dynamics of galactic clusters. A well known conjecture is the stability of spherical models which are…

Analysis of PDEs · Mathematics 2010-07-26 Mohammed Lemou , Florian Mehats , Pierre Raphael

We present an exact analytical solution of the Einstein equations with cosmological constant in a spatially flat Robertson-Walker metric. This is interpreted as an isotropic Lemaitre-type version of the cosmological Friedmann model.…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Ion I. Cotaescu , Dumitru N. Vulcanov