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200 papers

One of the stiffest equations of state for matter in a compact star is constant energy density and this generates the interior Schwarzschild radius to mass relation and the Misner maximum mass for relativistic compact stars. If dark matter…

Solar and Stellar Astrophysics · Physics 2016-03-25 José P. S. Lemos , Francisco J. Lopes , Gonçalo Quinta , Vilson T. Zanchin

General Relativity, in the absence of a cosmological constant, is an inevitable limit of Entangled Relativity, particularly when the universe is dominated by dust and/or electromagnetic radiation. In this communication, I emphasize that…

General Relativity and Quantum Cosmology · Physics 2024-05-06 Olivier Minazzoli

The effect of a generalized uncertainty principle on the structure of an ideal white dwarf star is investigated. The equation describing the equilibrium configuration of the star is a generalized form of the Lane-Emden equation. It is…

General Relativity and Quantum Cosmology · Physics 2017-01-11 Reza Rashidi

There are many different formulations of relativistic elasticity. Most of them are only concerned with formal questions rather than questions regarding the PDE point of view. The aim of this thesis is to obtain various local existence…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Michael Wernig-Pichler

A class of solutions of Einstein field equations satisfying Karmarkar embedding condition is presented which could describe static, spherical fluid configurations, and could serve as models for compact stars. The fluid under consideration…

General Relativity and Quantum Cosmology · Physics 2021-03-24 Lipi Baskey , Shyam Das , Farook Rahaman

The distributions of normal matter and of dark matter in the Galaxy are coupled to each other as they both move in the common gravitational potential. In order to fully exploit this interplay and to derive the various properties of dark…

Astrophysics of Galaxies · Physics 2013-12-16 Benjamin Burch , Ramanath Cowsik

This study presents a static, spherically symmetric configuration in which the interior geometry of a relativistic superdense star is modeled as a three-spheroid with constant $t_1$. The model is constructed using an analytical closed-form…

General Relativity and Quantum Cosmology · Physics 2026-01-07 Hemalatha R , Naren Babu O. , Narayanankutty Karuppath , Sabu M. C

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 present a model of relativistic elastic stars featuring scale invariance. This implies a linear mass-radius relation and the absence of a maximum mass. The most compact spherically symmetric configuration that is radially stable and…

General Relativity and Quantum Cosmology · Physics 2024-04-05 Artur Alho , José Natário , Paolo Pani , Guilherme Raposo

The main point of this paper is a suggestion about the proper treatment of the photon gas in a theory of stellar structure and other plasmas. This problem arises in the study of polytropic gas spheres, where we have already introduced some…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christian Fronsdal

In static and spherically symmetric spacetime, we solve the Einstein Maxwell equations. The effective gravitational potential and the electric field for charged anisotropic fluid are defined in terms of two free parameters. For such…

Solar and Stellar Astrophysics · Physics 2017-02-20 Safiqul Islam , Satadal Datta , Tapas K Das

We investigate spherically symmetric solutions to a recently proposed covariant and locally Lorentz-invariant varying speed of light theory. We find the metrics and variations in $c$ associated with the counterpart of black holes, the…

Astrophysics · Physics 2009-10-31 Joao Magueijo

We consider the general case of an accelerating, expanding and shearing model of a radiating relativistic star using Lie symmetries. We obtain the Lie symmetry generators that leave the equation for the junction condition invariant, and…

General Relativity and Quantum Cosmology · Physics 2015-06-23 G. Z. Abebe , S. D. Maharaj , K. S. Govinder

Neutron star matter spans a wide range of densities, from that of nuclei at the surface to exceeding several times normal nuclear matter density in the core. While terrestrial experiments, such as nuclear or heavy-ion collision experiments,…

High Energy Astrophysical Phenomena · Physics 2023-12-19 Suprovo Ghosh , Debarati Chatterjee , Jürgen Schaffner-Bielich

We generalise the Buchdahl-Bondi limit for the case of static, spherically symmetric, relativistic compact stars immersed in Schwarzschild vacuum in f(R)-theory of gravity, subject to very generic regularity, thermodynamic stability and…

General Relativity and Quantum Cosmology · Physics 2015-09-09 Rituparno Goswami , Sunil D. Maharaj , Anne Marie Nzioki

In this article we try to present spherically symmetric isotropic strange star model under the framework of $f(R,\mathcal{T})$ theory of gravity. To this end, we consider that the Lagrangian density is an arbitrary linear function of the…

General Relativity and Quantum Cosmology · Physics 2018-04-23 Debabrata Deb , Farook Rahaman , Saibal Ray , B. K. Guha

The recently introduced relativistic Lagrangian darkon fluid model (EPJ C (2015) 75:9) is generalized to a self-gravitating, irrotational, pressure-less and stress free geodesic fluid, whose energy-momentum tensor is dust-like with…

General Physics · Physics 2016-04-18 Peter C. Stichel

In the Rastall gravity a non-minimal coupling between geometry and matter fields is considered. Then the usual energy-momentum tensor conservation law is not valid. Here a Lagrangian formalism is proposed to the Rastall theory of gravity.…

General Relativity and Quantum Cosmology · Physics 2019-12-16 W. A. G. De Moraes , A. F. Santos

In this work we examine the effective four-dimensional world that emanates from a general class of static spherical Ricci-flat solutions in Kaluza-Klein gravity in $D$-dimensions. By means of dimensional reduction we obtain a family of…

General Relativity and Quantum Cosmology · Physics 2010-03-17 J. Ponce de Leon

The known static isotropic metric of Schwarzschild solution of Einstein equation cannot cover with the range of r<2MG, a new isotropic metric of Schwarzschild solution is obtained. The new isotropic metric has the characters: (1) It is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Mei