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We study the evolution of an anisotropic shear-free fluid with heat flux and kinematic self-similarity of the second kind. We found a class of solution to the Einstein field equations by assuming that the part of the tangential pressure…

General Relativity and Quantum Cosmology · Physics 2014-05-13 R. Chan , M. F. A. da Silva , C. F. C. Brandt

A new mechanism for causing naked singularities is found in an effective superstring theory. We investigate the gravitational collapse in a spherically symmetric Einstein-Maxwell-dilaton system in the presence of a pure cosmological…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Kengo Maeda , Takashi Torii , Makoto Narita

We investigate here spherically symmetric gravitational collapse in a spacetime with an arbitrary number of dimensions and with a general {\it type I} matter field, which is a broad class that includes most of the physically reasonable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Rituparno Goswami , Pankaj S Joshi

The final state--black hole or naked singularity--of the gravitational collapse of a marginally bound matter configuration in the presence of tangential stresses is classified, in full generality, in terms of the initial data and equation…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Sergio M. C. V. Goncalves , Sanjay Jhingan , Giulio Magli

To understand the nature of the black holes that exist in the Universe, it is also necessary to study what happens to the (quantum) matter that collapses and forms such objects. In this work, we consider a dust ball with an electrically…

General Relativity and Quantum Cosmology · Physics 2024-11-14 R. Casadio , R. da Rocha , A. Giusti , P. Meert

A class of spherical collapsing exact solutions with electromagnetic charge is derived. This class of solutions -- in general anisotropic -- contains however as a particular case the charged dust model already known in literature. Under…

General Relativity and Quantum Cosmology · Physics 2015-06-11 F. Cipolletta , R. Giambò

In the final stages of collapse, quantum radiation due to particle creation from a naked singularity is expected to be significantly different from black hole radiation. In certain models of collapse it has been shown that, neglecting the…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Cenalo Vaz , Louis Witten

A naked singularity is formed by the collapse of a Sine-Gordon soliton in 1+1 dimensional dilaton gravity with a negative cosmological constant. We examine the quantum stress tensor resulting from the formation of the singularity.…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Cenalo Vaz , Louis Witten

It has been suggested that a naked singularity may be a good candidate for a strong gravitational wave burster. The naked singularity occurs in the generic collapse of an inhomogeneous dust ball. We study odd-parity mode of gravitational…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Hideo Iguchi , Tomohiro Harada , Ken-ichi Nakao

We investigate the unhindered gravitational collapse of a homogeneous scalar field with nonzero potential, a two-dimensional analog of the Mexican hat-shaped Higgs field potential. The collapsing scalar field is surrounded by an exterior…

General Relativity and Quantum Cosmology · Physics 2022-04-01 Karim Mosani , Dipanjan Dey , Kaushik Bhattacharya , Pankaj S. Joshi

Recent developments on the final state of a gravitationally collapsing massive matter cloud are summarized and reviewed here. After a brief background on the problem, we point out how the black hole and naked singularity end states arise…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pankaj S Joshi

Covariant equations characterizing the strength of a singularity in spherical symmetry are derived and several models are investigated. The difference between central and non-central singularities is emphasised. A slight modification to the…

General Relativity and Quantum Cosmology · Physics 2016-08-25 Brien C. Nolan

We establish the formalism in the nonsymmetric gravitational theory (NGT) for stellar equilibrium and gravitational collapse. We study the collapse of a pressureless, spherically symmetric dust cloud. By assuming that the interior solution…

Astrophysics · Physics 2008-02-03 J. W. Moffat

We construct here a class of collapsing scalar field models with a non-zero potential, which result in a naked singularity as collapse end state. The weak energy condition is satisfied by the collapsing configuration. It is shown that…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Rituparno Goswami , Pankaj S Joshi

We generalize here our earlier results on particle acceleration by naked singularities. We showed recently[1] that the naked singularities that form due to gravitational collapse of massive stars provide a suitable environment where…

General Relativity and Quantum Cosmology · Physics 2011-03-22 Mandar Patil , Pankaj S. Joshi , Daniele Malafarina

The singularity structure of charged spherical collapse is studied by considering the evolution of the gravity-scalar field system. A detailed examination of the geometry at late times strongly suggests the validity of the mass-inflation…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Patrick R. Brady , John D. Smith

A major issue in general relativity and blackhole physics today is to determine the conditions when the spacetime singularities forming as end-states of gravitational collapse are visible to external observers, and when these are hidden…

General Relativity and Quantum Cosmology · Physics 2025-08-21 Koushiki , Pankaj S. Joshi

We consider a gravastar model made of anisotropic dark energy with an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ with an external de Sitter-Schwarzschild region. It is found that in…

General Relativity and Quantum Cosmology · Physics 2015-03-17 C. F. C. Brandt , R. Chan , M. F. A. da Silva , P. Rocha

We give a model of the higher-dimensional spherically symmetric gravitational collapse of a dust cloud in Einstein-Gauss-Bonnet gravity. A simple formulation of the basic equations is given for the spacetime $M \approx M^2 \times K^{n-2}$…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Hideki Maeda

The present work includes an analytical investigation of a collapsing spherical star in f (R) gravity. The interior of the collapsing star admits a conformal flatness. Information regarding the fate of the collapse is extracted from the…

General Relativity and Quantum Cosmology · Physics 2018-11-07 Soumya Chakrabarti , Rituparno Goswami , Sunil Maharaj , Narayan Banerjee