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We construct a class of spherically symmetric collapse models in which a naked singularity may develop as the end state of collapse. The matter distribution considered has negative radial and tangential pressures, but the weak energy…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Rituparno Goswami , Pankaj S. Joshi , Cenalo Vaz , Louis Witten

We study the occurrence of naked singularities in the spherically symmetric collapse of a charged null fluid in an expanding deSitter background - a piece of charged Vaidya-deSitter spacetime. The necessary conditions for the formation of a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. Beesham , S. G. Ghosh

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

Generalizing earlier results of Joshi and Dwivedi (Commun. Math. Phys. 146, 333 (1992); Lett. Math. Phys. 27, 235 (1993)), we analyze here the spherically symmetric gravitational collapse of a matter cloud with a general form of matter for…

General Relativity and Quantum Cosmology · Physics 2009-10-22 I. H. Dwivedi , P. S. Joshi

We investigate the occurrence of naked singularities, local and global, in the incoming Vaidya spacetimes with zero initial mass. While it is well-known that these spacetimes admit locally and globally naked singularities, we demonstrate…

General Relativity and Quantum Cosmology · Physics 2022-09-20 James Wheeler

Global visibility of naked singularities is analyzed here for a class of spherically symmetric spacetimes, extending previous studies - limited to inhomogeneous dust cloud collapse - to more physical valid situations in which pressures are…

General Relativity and Quantum Cosmology · Physics 2009-11-11 R. Giambo'

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

We investigate what are the key physical features that cause the development of a naked singularity, rather than a black hole, as the end-state of spherical gravitational collapse. We show that sufficiently strong shearing effects near the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Pankaj S. Joshi , Naresh Dadhich , Roy Maartens

We consider spherically symmetric spacetimes with matter whose timelike flow is assumed to be shear-free. A number of results on the formation and visibility of spacetime singularities is proven, with the main one being that shear-free…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Sergio M. C. V. Goncalves

A theorem, giving necessary and sufficient condition for naked singularity formation in spherically symmetric non static spacetimes under hypotheses of physical acceptability, is formulated and proved. The theorem relates existence of…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Roberto Giambo' , Fabio Giannoni , Giulio Magli , Paolo Piccione

There are non-radial null geodesics emanating from the shell focusing singularity formed at the symmetric center in a spherically symmetric dust collapse. In this article, assuming the self-similarity in the region filled with the dust…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Ken-ichi Nakao , Naoki Kobayashi , Hideki Ishihara

Considering the evolution of a perfect fluid with self-similarity of the second kind, we have found that an initial naked singularity can be trapped by an event horizon due to collapsing matter. The fluid moves along time-like geodesics…

General Relativity and Quantum Cosmology · Physics 2012-10-25 C. F. C. Brandt , R. Chan , M. F. A. da Silva , J. F. Villas da Rocha

Continued gravitational collapse gives rise to curvature singularities. If a curvature singularity is globally naked then the space-time may be causally future ill-behaved admitting closed time-like or null curves which extend to asymptotic…

General Relativity and Quantum Cosmology · Physics 2010-11-11 F. de Felice

Primordial black hole formation has been discussed widely, when density perturbations in the early universe cause matter to collapse gravitationally, giving rise to these ultra-compact objects. We propose and point out that such a…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Pankaj S. Joshi , Sudip Bhattacharyya

In this paper, we study the gravitational collapse of null dust in the cylindrically symmetric spacetime. The naked singularity necessarily forms at the symmetry axis. We consider the situation in which null dust is emitted again from the…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Yasunari Kurita , Ken-ichi Nakao

It is generally believed that the shadows of either a black hole or naked singularity arise due to photon spheres developing in these spacetimes. Here we propose a new spherically symmetric naked singularity spacetime solution of Einstein…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Ashok B. Joshi , Dipanjan Dey , Pankaj S. Joshi , Parth Bambhaniya

Gravitational collapse is one of the most fruitful subjects in gravitational physics. It is well known that singularity formation is inevitable in complete gravitational collapse. It was conjectured that such a singularity should be hidden…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Tomohiro Harada , Hideo Iguchi , Ken-ichi Nakao

We study the evolution of bubble spacetimes in vacuum and electrovac scenarios by numerical means. We find strong evidence against the formation of naked singularities in (i) scenarios with negative masses displaying initially collapsing…

High Energy Physics - Theory · Physics 2009-11-10 Olivier Sarbach , Luis Lehner

We describe a simple method of determining whether the singularity that forms in the spherically symmetric collapse of inhomogeneous dust is naked or covered. This derivation considerably simplifies the analysis given in the earlier…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Sukratu Barve , T. P. Singh , Cenalo Vaz , Louis Witten

Electromagnetic waves propagating in the background provided by a spacetime hosting a strong curvature, naked singularity, are fully studied. The analysis is performed not only in the realm of geometrical optics -- which, not surprisingly,…

General Relativity and Quantum Cosmology · Physics 2025-04-25 Franco Fiorini , Santiago Hernandez , Juan Manuel Paez
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