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We investigate the occurrence of shell crossing singularities in quasi-spherical Szekeres dust models with or without a cosmological constant. We study the conditions for shell crossing singularity both from physical and geometrical point…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Subenoy Chakraborty , Ujjal Debnath

We revisit the gravitational collapse of spherically symmetric Lema\^itre - Tolman - Bondi (LTB) dust models. A sufficient condition for global visibility of singularity is given. This condition also allows us to extend the condition of…

General Relativity and Quantum Cosmology · Physics 2021-02-04 Sanjay Jhingan , Sahal Kaushik

We investigate the occurrence and nature of naked singularities in the gravitational collapse of a self-similar adiabatic perfect fluid in a five dimensional space-time. The naked singularities are found to be gravitationally strong in the…

General Relativity and Quantum Cosmology · Physics 2015-06-23 S G Ghosh , S B Sarwe , R V Saraykar

We study the end stages of gravitational collapse of the thin shell of matter in ingoing Eddington-Finkelstein coordinates. We use the functional Schrodinger formalism to capture quantum effects in the near singularity limit. We find that…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Anshul Saini , Dejan Stojkovic

We comment here on the results in Ref [4] that showed naked singularities in dynamical gravitational collapse of inhomogeneous dust to be stable but non-generic. The definition of genericity used there is reconsidered. We point out that…

General Relativity and Quantum Cosmology · Physics 2012-07-17 Ravindra V. Saraykar , Pankaj S. Joshi

We study spherically symmetric gravitational collapse of a homogeneous perfect fluid in Rastall gravity. Considering a linear equation of state (EoS) for the fluid profiles, we examine the conditions under which the collapse scenario could…

General Relativity and Quantum Cosmology · Physics 2019-05-08 A. H. Ziaie , H. Moradpour , S. Ghaffari

There are known models of spherical gravitational collapse in which the collapse ends in a naked shell-focusing singularity for some initial data. If a massless scalar field is quantized on the classical background provided by such a star,…

General Relativity and Quantum Cosmology · Physics 2009-12-31 Tomohiro Harada , Hideo Iguchi , Ken-ichi Nakao , T. P. Singh , Takahiro Tanaka , Cenalo Vaz

We develop here a new procedure within Einstein's theory of gravity to generate equilibrium configurations that result as the final state of gravitational collapse from regular initial conditions. As a simplification, we assume that the…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Pankaj S. Joshi , Daniele Malafarina , Ramesh Narayan

The general formulas of a non-rotating dynamic thin shell that connects two arbitrary cylindrical regions are given using Israel's method. As an application of them, the dynamics of a thin shell made of counter-rotating dust particles,…

General Relativity and Quantum Cosmology · Physics 2014-11-17 P. R. C. T. Pereira , Anzhong Wang

We present two-dimensional simulations of finite, self-gravitating gaseous sheets. Unlike the case of infinite sheets, such configurations do not constitute equilibrium states but instead are subject to global collapse unless countered by…

Astrophysics · Physics 2009-11-10 Andreas Burkert , Lee Hartmann

There is a viable vector-tensor gravity (VTG) theory, whose vector field produces repulsive forces leading to important effects. In the background universe, the effect of these forces is an accelerated expansion identical to that produced…

General Relativity and Quantum Cosmology · Physics 2020-12-01 R. Dale , D. Sáez

We analyze the null geodesic equations in five dimensional spherically symmetric spacetime with collapsing inhomogeneous dust cloud. By using a new method, we prove the existence and non-existence of solutions to null geodesic equation…

General Relativity and Quantum Cosmology · Physics 2016-07-12 Ryosuke Mizuno , Seiju Ohashi , Tetsuya Shiromizu

We study the effects of shear and density inhomogeneities in the formation of naked singularities in spherically symmetric dust space--times. We find that in general neither of these physical features alone uniquely specifies the end state…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Filipe C. Mena , Brien C. Nolan , Reza Tavakol

In the case of unhindered gravitational collapse of matter cloud governed by the Lemaitre-Tolman-Bondi (LTB) spacetime, the end-state singularity is either locally visible, globally visible or completely hidden. We have a past-null…

General Relativity and Quantum Cosmology · Physics 2024-02-23 Ashok B. Joshi , Karim Mosani , Pankaj S. Joshi

The gravitational collapse of an infinite cylindrical thin shell of generic matter in an otherwise empty spacetime is considered. We show that geometries admitting two hypersurface orthogonal Killing vectors cannot contain trapped surfaces…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Sergio M. C. V. Goncalves

We analyze the evolution of a homogenous and pressureless ball of dust (or "star") in ghost-free massive gravity on de Sitter spacetime. We find that gravitational collapse does not take place for all parameters of the massive gravity…

High Energy Physics - Theory · Physics 2021-09-23 Roman Berens , Luke Krauth , Rachel A. Rosen

We investigate the occurrence of naked singularities in the spherically symmetric, plane symmetric and cylindrically symmetric collapse of charged null fluid in an anti-de Sitter background. The naked singularities are found to be strong in…

General Relativity and Quantum Cosmology · Physics 2008-11-26 S. G. Ghosh

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

We consider here the effects of a non-vanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that depending on the nature of the initial data from which the collapse evolves, and for a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 S. S. Deshingkar , S. Jhingan , A. Chamorro , P. S. Joshi

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