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We studied a new class of interior solutions that are singular-free and useful for describing anisotropic compact star objects with spherically symmetric matter distribution. We have considered metric potential selecting B_0^2…

General Relativity and Quantum Cosmology · Physics 2023-10-19 B. S. Ratanpal , Rinkal Patel

Ivanov pointed out substantial analytical difficulties associated with self-gravitating, static, isotropic fluid spheres when pressure explicitly depends on matter density. Simplification achieved with the introduction of electric charge…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Victor Varela , Farook Rahaman , Saibal Ray , Koushik Chakraborty , Mehedi Kalam

The main objective of this article is to study the viable compact stellar structures in non-Riemannian geometry, i.e., $f(\mathbb{Q},T)$ theory, where $\mathbb{Q}$ defines the non-metricity and $T$ represents trace of the stress-energy…

General Relativity and Quantum Cosmology · Physics 2024-04-02 M. Zeeshan Gul , M. Sharif , Adeeba Arooj

We have constructed star models consisting of four parts: (i) a homogeneous inner core with anisotropic pressure (ii) an infinitesimal thin shell separating the core and the envelope; (iii) an envelope of inhomogeneous density and isotropic…

General Relativity and Quantum Cosmology · Physics 2012-10-25 R. Chan , M. F. A. da Silva , J. F. Villas da Rocha

We study charged fluid spheres under the 4-dimensional Einstein-Maxwell space-time. The solutions thus obtained admitting conformal motion. We also investigate whether the solutions set provide electromagnetic mass models such that the…

General Relativity and Quantum Cosmology · Physics 2011-07-04 Saibal Ray , A A Usmani , F Rahaman , M Kalam , K Chakraborty

The inhomogeneous distribution of matter in the non-linear regime of galaxies, clusters of galaxies and voids is described by an exact, spherically symmetric inhomogeneous solution of Einstein's gravitational field equations, corresponding…

Astrophysics · Physics 2009-11-11 J. W. Moffat

We present two classes of inhomogeneous, spherically symmetric solutions of the Einstein-Maxwell-Perfect Fluid field equations with cosmological constant generalizing the Vaidya-Shah solution. Some special limits of our solution reduce to…

General Relativity and Quantum Cosmology · Physics 2019-10-09 Metin Gurses , Yaghoub Heydarzade

We examine static perfect fluid spheres in the presence of a cosmological constant. New exact matter solutions are discussed which require the Nariai metric in the vacuum region. We generalize the Einstein static universe such that neither…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christian G. Boehmer , Gyula Fodor

In this article, we attempt to find a singularity free solution of Einstein's field equations for compact stellar objects, precisely strange (quark) stars, considering Schwarzschild metric as the exterior spacetime. To this end, we consider…

General Relativity and Quantum Cosmology · Physics 2017-10-19 Debabrata Deb , Sourav Roy Chowdhury , Saibal Ray , Farook Rahaman , B. K. Guha

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

The main aim of this paper is to obtain a completely new relativistic non-singular model for static, spherically symmetric isotropic celestial compact stars in the $f(R, T)$ gravity scenario. In this regard, we have considered the isotropic…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Nayan Sarkar , Susmita Sarkar , Banashree Sen Moumita Sarkar , Farook Rahaman

We present an anisotropic cosmological model based on a new exact solution of Einstein equations. The matter content consists of an anisotropic scalar field minimally coupled to gravity and of two isotropic perfect fluids that represent…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Saulo Carneiro , Guillermo A. Mena Marugan

The goal of this work is to develop physical models for spherically symmetric systems in the realm of $f(Q)$ gravity. The field equations are set up for anisotropic fluid and formulate these equations using physical ansatz of Vaidya-Tikekar…

General Relativity and Quantum Cosmology · Physics 2025-03-28 M. Awais , M. Azam

The present work deals with homogeneous and isotropic FLRW model of the Universe having a system of non-interacting diffusive cosmic fluids with barotropic equation of state (constant or variable equation of state parameter). Due to…

General Relativity and Quantum Cosmology · Physics 2019-02-22 Subhayan Maity , Pritikana Bhandari , Subenoy Chakraborty

We revive the historically first dark matter model based on neutrinos, but with an additional assumption that neutrinos might exist in tachyonic almost sterile states. To this end, we propose a group-theoretical algorithm for the…

General Physics · Physics 2016-04-13 Maxim A. Makukov , Eduard G. Mychelkin , Vladimir L. Saveliev

We present a class of exact solutions of Einstein field equations for a shear-free spherically symmetric anisotropic fluid undergoing radial heat flow. The interior metric fulfilled all the relevant physical and thermodynamic conditions and…

General Relativity and Quantum Cosmology · Physics 2016-01-21 B. C. Tewari , Kali Charan

In this paper, we derive some new invariant solutions of dark energy models in cylindrically symmetric space-time. To quantify the deviation of pressure from isotropy, we introduce three different time dependent skewness parameters along…

General Relativity and Quantum Cosmology · Physics 2014-09-10 Anil Kumar Yadav , Ahmad T Ali

In this work we study the influence of isotropic and anisotropic fluids on the spherically symmetric warp metric. We evaluate the energy conditions and the influence of including a cosmological constant type term. We find that, considering…

General Relativity and Quantum Cosmology · Physics 2023-05-09 Gabriel Abellán , Nelson Bolívar , Ivaylo Vasilev

Static spherically symmetric anisotropic source has been studied for the Einstein-Maxwell field equations assuming the erstwhile cosmological constant $ \Lambda $ to be a space-variable scalar, viz., $ \Lambda = \Lambda(r) $. Two cases have…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Saibal Ray , Sumana Bhadra , Anand S. Sengupta

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