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We investigate the role played by density inhomogeneities and dissipation on the final outcome of collapse of a self-gravitating sphere. By imposing a perturbative scheme on the thermodynamical variables and gravitational potentials we…

General Relativity and Quantum Cosmology · Physics 2021-02-12 Nolene F. Naidu , Robert S. Bogadi , Anand Kaisavelu , Megan Govender

Assuming the weak energy condition, we study the nature of the non-central shell-focussing singularity which can form in the gravitational collapse of a spherical compact object in classical general relativity. We show that if the radial…

General Relativity and Quantum Cosmology · Physics 2009-10-28 F. I. Cooperstock , S. Jhingan , P. S. Joshi , T. P. Singh

A class of solutions to Einstein field equations is studied, which represents gravitational collapse of thick spherical shells made of self-similar and shear-free fluid with heat flow. It is shown that such shells satisfy all the energy…

General Relativity and Quantum Cosmology · Physics 2009-11-07 R. Chan , M. F. A. da Silva , Jaime F. Villas da Rocha

The causal character of the zero-areal-radius (R=0) singularity in spherically symmetric spacetimes is studied. By using the techniques of the qualitative behaviour of dynamic systems, we are able to present the most comprehensive scheme so…

General Relativity and Quantum Cosmology · Physics 2012-04-23 Francesc Fayos , Ramon Torres

Starting from the Oppenheimer-Snyder solution for gravitational collapse, we show by putting it into the harmonic coordinates, for which the distant Riemann metric is galilean, that the final state of collapse for a collapsed star of any…

General Relativity and Quantum Cosmology · Physics 2011-04-01 Trevor W. Marshall

A new model is proposed to a collapsing star consisting of an initial inhomogeneous energy density and anisotropic pressure fluid with shear, radial heat flow and outgoing radiation. In previous papers one of us has always assumed an…

General Relativity and Quantum Cosmology · Physics 2014-06-03 G. Pinheiro , R. Chan

We model a radiating star undergoing dissipative gravitational collapse in the form of radial heat flux. The exterior of the collapsing star is described by the generalised Vaidya solution representing a mixture of null radiation and…

General Relativity and Quantum Cosmology · Physics 2017-09-13 NF Naidu , M Govender , S Thirukkanesh , SD Maharaj

We show that under particular circumstances a general relativistic spherically symmetric bounded distribution of matter could satisfy a nonlocal equation of state. This equation relates, at a given point, the components of the corresponding…

General Relativity and Quantum Cosmology · Physics 2011-07-19 H. Hernandez , L. A. Nunez , U. Percoco

This study examines the gravitational collapse of an overdense dark matter region in a coupled scalar field dark energy scenario within a flat FLRW background. It finds that, depending on the initial conditions, some overdense regions avoid…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Priyanka Saha , Dipanjan Dey , Kaushik Bhattacharya

We present a new shear free model for the gravitational collapse of a spherically symmetric charged body. We propose a dissipative contraction with radiation emitted outwards. The Einstein field equations, using the junction conditions and…

General Relativity and Quantum Cosmology · Physics 2013-01-10 G. Pinheiro , R. Chan

Numerical studies of gravitational collapse in isotropic coordinates have recently shown an interesting connection between the gravitational Lagrangian and black hole thermodynamics. A study of the actual spacetime was not the main focus of…

General Relativity and Quantum Cosmology · Physics 2012-02-24 Hugues Beauchesne , Ariel Edery

This paper studies intermediate homogenization of inhomogeneous cosmological models. It shows that spherically symmetric models, regardless of the equation of state, can undergo intermediate homogenization, i.e. a model can approach a…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-27 Krzysztof Bolejko , William R. Stoeger

We study numerically gravitational collapse of a spherically symmetric instanton particle in five dimensions. We show that the late stages of the process are characterized by a nearly constant ``free energy'', the value of which matches…

High Energy Physics - Theory · Physics 2008-11-26 Z. Gecse , S. Khlebnikov

This paper investigates the five-dimensional(5D) spherically symmetric gravitational collapse with positive cosmological constant in the presence of an electromagnetic field. The junction conditions between the 5D non-static interior and…

General Relativity and Quantum Cosmology · Physics 2015-05-18 M. Sharif , G. Abbas

The kinetic motion of the stars of a galaxy is considered within the framework of a relativistic scalar theory of gravitation. This model, even though unphysical, may represent a good laboratory where to study in a rigorous, mathematical…

Mathematical Physics · Physics 2017-08-23 Simone Calogero

Gravitational collapse is analyzed in the Brane-World by arguing that regularity of five-dimensional geodesics require that stars on the brane have an atmosphere. For the simple case of a spherically symmetric cloud of non-dissipating dust,…

High Energy Physics - Theory · Physics 2015-06-26 R. Casadio , C. Germani

In the mean field limit, isolated gravitational systems often evolve towards a steady state through a violent relaxation phase. One question is to understand the nature of this relaxation phase, in particular the role of radial…

Astrophysics of Galaxies · Physics 2018-12-19 Anaelle Halle , Stephane Colombi , Sebastien Peirani

In this paper we consider the negative energy problem in generalized Vaidya spacetime. We consider several models when we have the naked singularity as a result of the gravitational collapse. In these models we investigate the geodesics for…

General Relativity and Quantum Cosmology · Physics 2022-09-23 Vitalii Vertogradov

We study here the evolution of a massless scalar field in a spacetime, developing from a regular initial spacelike surface. The Einstein equations and regularity and boundary conditions governing the same are specified. Both homogeneous and…

General Relativity and Quantum Cosmology · Physics 2009-12-13 Swastik Bhattacharya , Rituparno Goswami , Pankaj S. Joshi

We investigate the spherically-symmetric gravitational collapse of a massless scalar field in the framework of a type-II minimally modified gravity theory called VCDM. This theory propagates only two local physical degrees of freedom…

General Relativity and Quantum Cosmology · Physics 2024-01-08 Atabak Fathe Jalali , Paul Martens , Shinji Mukohyama