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The charged anisotropic star on paraboloidal spacetime is reported by choosing particular form of radial pressure and electric field intensity. The non-singular solution of Einstein-Maxwell system of equation have been derived and it is…

General Relativity and Quantum Cosmology · Physics 2016-04-07 B. S. Ratanpal , Jaita Sharma

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 address the existence of globally neutral neutron star configurations in contrast with the traditional ones constructed by imposing local neutrality. The equilibrium equations describing this system are the Einstein-Maxwell equations…

Solar and Stellar Astrophysics · Physics 2009-11-25 Jorge A. Rueda , Remo Ruffini , She-Sheng Xue

General relativity probably is not the definitive theory of gravity, due a number or issues, both from the theoretical and from the observational point of view. Alternative theories of gravity were conceived to extend general relativity and…

High Energy Astrophysical Phenomena · Physics 2021-05-13 Jacopo Soldateschi , Niccolò Bucciantini , Luca Del Zanna

In the present article we have obtained new set of exact solutions of Einstein field equations for anisotropic fluid spheres by using the Herrera et al.[1] algorithm. The anisotropic fluid solution so obtained join continuously to…

General Relativity and Quantum Cosmology · Physics 2015-09-30 S. K. Maurya , Y. K. Gupta , M. K. Jasim

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

We analyse shear-free spherically symmetric relativistic models of gravitating fluids with heat flow and electric charge defined on higher dimensional manifolds. The solution to the Einstein-Maxwell system is governed by the pressure…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Y. Nyonyi , S. D. Maharaj , K. S. Govinder

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

In this work, we generate two static anisotropic solutions for a sphere containing quark matter in the framework of self-interacting Brans-Dicke theory. For this purpose, we add an anisotropic source in the seed distribution and decouple…

General Relativity and Quantum Cosmology · Physics 2023-07-26 M. Sharif , Amal Majid

In this paper, we study the physical characteristics of anisotropic spherically symmetric quark star candidates for $R+2\sigma T$ gravity model, where $R$, $\sigma$ and $T$ depict scalar curvature, coupling parameter, and the trace of the…

General Relativity and Quantum Cosmology · Physics 2020-01-08 M. Sharif , Arfa Waseem

In this article, we present a class of relativistic solutions describing spherically symmetric and static anisotropic stars in hydrostatic equilibrium. For this purpose, we consider a particularized matric potential, namely, Buchdahl ansatz…

General Relativity and Quantum Cosmology · Physics 2021-08-03 S. K. Maurya , Ayan Banerjee , M. K. Jasim , J. Kumar , A. K. Prasad , Anirudh Pradhan

We find new classes of exact solutions to the Einstein-Maxwell system of equations for a charged sphere with a particular choice of the electric field intensity and one of the gravitational potentials. The condition of pressure isotropy is…

General Relativity and Quantum Cosmology · Physics 2009-03-19 K. Komathiraj , S. D. Maharaj

Quasi-equilibrium models of uniformly rotating axisymmetric and triaxial quark stars are computed in general relativistic gravity scenario. The Isenberg-Wilson-Mathews (IWM) formulation is employed and the Compact Object CALculator (COCAL)…

High Energy Astrophysical Phenomena · Physics 2018-02-15 Enping Zhou , Antonios Tsokaros , Luciano Rezzolla , Renxin Xu , Kōji Uryū

In this paper, the gravitational field equations for static spherically symmetric perfect fluid models with a polytropic equation of state, $p=k\rho^{1+1/n}$, are recast into two complementary 3-dimensional {\it regular} systems of ordinary…

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

We show that the inclusion of simple anisotropic pressures stops the isotropic Friedmann universe being a stable attractor as an initial or final singularity is approached when pressures can exceed the energy density. This shows that the…

General Relativity and Quantum Cosmology · Physics 2014-11-20 John D Barrow , Kei Yamamoto

In this article we propose a relativistic model of a static spherically symmetric anisotropic strange star with the help of Tolman-Kuchowicz (TK) metric potentials [Tolman, Phys. Rev. {\bf55}, 364 (1939) and Kuchowicz, Acta Phys. Pol.…

General Relativity and Quantum Cosmology · Physics 2019-10-02 Suparna Biswas , Dibyendu Shee , Saibal Ray , F. Rahaman , B. K. Guha

The paper considers a set of equations describing the static isotropic gravity field of a macroscopic body within the framework of the theory of gravity with a constraint. A general approximate solution of these equations is obtained. The…

General Relativity and Quantum Cosmology · Physics 2024-02-08 Alexander P. Sobolev , Aleksey Sobolev

We derive upper and lower limits for the basic physical parameters (mass-radius ratio, anisotropy, redshift and total energy) for arbitrary anisotropic general relativistic matter distributions in the presence of a cosmological constant.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. G. Boehmer , T. Harko

A family of exact relativistic stellar models is described. The family generalizes Buchdahl's n=1 polytropic solution. The matter content is a perfect fluid and, excluding Buchdahl's original model, it behaves as a liquid at low pressures…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Kjell Rosquist

The collective modes of QCD at temperatures and densities above its phase-transition are analyzed for isotropic systems as well as for systems having an anisotropy in momentum-space using the HTL approximation. For isotropic systems,…

High Energy Physics - Phenomenology · Physics 2007-05-23 Paul Romatschke