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Related papers: Class I polytropes for anisotropic matter

200 papers

In this manuscript, we put forth a general scheme for defining initial value problems from Einstein's equations of General Relativity constrained by homogeneous and isotropic expansion. The cosmological models arising as solutions are…

General Relativity and Quantum Cosmology · Physics 2024-08-06 Leandro G. Gomes , Marcelo A. C. Nogueira , Lucas Ruiz dos Santos

Seven new solutions to the interior static and spherically symmetric Einstein's field equations (EFE) are found and investigated. These new solutions are a generalisation of the quadratic density fall-off profile of the Tolman VII solution.…

General Relativity and Quantum Cosmology · Physics 2016-05-02 Ambrish M. Raghoonundun

A modified version of the conditional symmetry method, together with the classical method, is used to obtain new classes of elliptic solutions of the isentropic ideal compressible fluid flow in (3+1) dimensions. We focus on those types of…

Mathematical Physics · Physics 2009-11-13 R. Conte , A. M. Grundland , B. Huard

We present a general method to obtain static anisotropic spherically symmetric solutions, satisfying a nonlocal equation of state, from known density profiles. This equation of state describes, at a given point, the components of the…

General Relativity and Quantum Cosmology · Physics 2016-08-15 H. Hernández , L. A. Núñez

We describe an ansatz for symmetry reduction of the Lane-Emden equation for an arbitrary polytropic index n, admitting only one symmetry generator. For the reduced first order differential equation it is found that standard reduction…

Mathematical Physics · Physics 2008-12-03 Babur M. Mirza

We establish an algorithm that produces a new solution to the Einstein field equations, with an anisotropic matter distribution, from a given seed isotropic solution. The new solution is expressed in terms of integrals of known functions,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. D. Maharaj , M. Chaisi

Expansion of a locally equilibrated fluid is considered in an anisotropic space-time given by Bianchi type I metric. Starting from isotropic equilibrium phase-space distribution function in the local rest frame, we obtain expressions for…

General Relativity and Quantum Cosmology · Physics 2018-05-08 Ashutosh Dash , Amaresh Jaiswal

This is the second of a series of papers extending the 1+3 covariant and gauge invariant treatment of kinetic theory to an examination of Cosmic Microwave Background temperature anisotropies arising from inhomogeneities in the early…

Astrophysics · Physics 2008-12-01 Tim Gebbie , Peter Dunsby , George Ellis

We establish a new algorithm that generates a new solution to the Einstein field equations, with an anisotropic matter distribution, from a seed isotropic solution. The new solution is expressed in terms of integrals of an isotropic…

General Relativity and Quantum Cosmology · Physics 2014-11-17 M. Chaisi , S. D. Maharaj

We present model for anisotropic compact star under the general theory of relativity of Einstein. In the study a 4-dimensional spacetime has been considered which is embedded into the 5-dimensional flat metric so that the spherically…

General Physics · Physics 2018-08-01 S. K. Maurya , Saibal Ray , Shounak Ghosh , Sarbajit Manna , Smitha T. T

In this paper, we found new classes of solutions to the Einstein-Maxwell field equations with matter anisotropic distribution incorporating a particular form of electric field intensity within the framework of general relativity. We use a…

General Relativity and Quantum Cosmology · Physics 2023-10-03 Manuel Malaver , Rajan Iyer

We study the global dynamical behavior of spatially homogeneous solutions of the Einstein equations in Bianchi type I symmetry, where we use non-tilted elastic matter as an anisotropic matter model that naturally generalizes perfect fluids.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Simone Calogero , J. Mark Heinzle

We construct a covariant version of the Tolman-Oppenheimer-Volkoff equations in the case of isotropic sources. The new equations make evident the mathematical problems in the determination of interior solutions of relativistic stellar…

General Relativity and Quantum Cosmology · Physics 2018-06-27 Sante Carloni , Daniele Vernieri

A new class of solutions describing the composition of compact stars has been proposed, assuming that the fluid distribution inside the star is anisotropic. This is achieved by assuming the appropriate metric potential and then solving…

General Physics · Physics 2020-03-11 D. M. Pandya , B. Thakore , R. Goti , J. P. Rank , S. Shah

We consider static charged fluid spheres with a cosmological constant. We assume a polytropic equation of state, $p \propto \rho^\Gamma$, and a power law charge distribution, $q\propto r^n$. Using this, we convert the generalised…

General Relativity and Quantum Cosmology · Physics 2026-03-30 Alex Stornelli , Anish Agashe

In this article we obtain a new anisotropic solution for Einstein's field equation of embedding class one metric. The solution is representing the realistic objects such as $Her~X-1$ and $RXJ~1856-37$. We perform detailed investigation of…

General Physics · Physics 2016-04-27 S. K. Maurya , Y. K. Gupta , Baiju Dayanandan , Saibal Ray

We present an algorithm to generalize a plethora of well-known solutions to Einstein field equations describing spherically symmetric relativistic fluid spheres by relaxing the pressure isotropy condition on the system. By suitably fixing…

General Physics · Physics 2018-02-14 S. Thirukkanesh , F. C. Ragel , Ranjan Sharma , Shyam Das

Density linear perturbations in Einstein-Cartan two fluid cosmologies where the outer model is an isotropic Friedmann solution with closed model while the inner model is a flat anisotropic Einstein-Cartan (EC) cosmology with shear are…

Astrophysics · Physics 2007-05-23 L. C. Garcia de Andrade

Spherically symmetric relativistic stars with the polytropic equation of state (EoS), which possess the local pressure anisotropy, are considered within the framework of general relativity. The generalized Lane-Emden equations are derived…

General Relativity and Quantum Cosmology · Physics 2018-01-12 A. A. Isayev

Two distinct non-singular interior models that describe anisotropic spherical configurations are presented in this work. We develop the Einstein field equations and the associated mass function in accordance with a static spherical…

General Relativity and Quantum Cosmology · Physics 2025-10-10 M. Sharif , Tayyab Naseer , Hira Shadab