scholarly journals Perihelion precession and shadows near black holes and naked singularities

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Dipanjan Dey ◽  
Rajibul Shaikh ◽  
Pankaj S. Joshi
Keyword(s):  
Black Holes ◽  
Perihelion Precession ◽  
Naked Singularities

scholarly journals HIGHER DIMENSIONAL INHOMOGENEOUS DUST COLLAPSE AND COSMIC CENSORSHIP

2002 ◽  
Vol 17 (20) ◽  
pp. 2747-2747
Author(s):  
A. BEESHAM
Keyword(s):  
Black Holes ◽  
Cosmic Censorship ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Naked Singularities ◽  
Singularity Theorems ◽  
Sitter Spacetime ◽  
Higher Dimensional ◽  
Cosmic Censorship Hypothesis ◽  
Strong Curvature

The singularity theorems of general relativity predict that gravitational collapse finally ends up in a spacetime singularity1. The cosmic censorship hypothesis (CCH) states that such a singularity is covered by an event horizon2. Despite much effort, there is no rigorous formulation or proof of the CCH. In view of this, examples that appear to violate the CCH and lead to naked singularities, in which non-spacelike curves can emerge, rather than black holes, are important to shed more light on the issue. We have studied several collapse scenarios which can lead to both situations3. In the case of the Vaidya-de Sitter spacetime4, we have shown that the naked singularities that arise are of the strong curvature type. Both types of singularities can also arise in higher dimensional Vaidya and Tolman-Bondi spacetimes, but black holes are favoured in some sense by the higher dimensions. The charged Vaidya-de Sitter spacetime also exhibits both types of singularities5.

scholarly journals GENERICITY ASPECTS IN GRAVITATIONAL COLLAPSE TO BLACK HOLES AND NAKED SINGULARITIES

2012 ◽  
Vol 21 (08) ◽  
pp. 1250066 ◽  
Author(s):  
PANKAJ S. JOSHI ◽  
DANIELE MALAFARINA ◽  
RAVINDRA V. SARAYKAR
Keyword(s):  
Black Holes ◽  
Initial Data ◽  
Gravitational Collapse ◽  
Naked Singularity ◽  
Matter Field ◽  
Einstein Equations ◽  
Type I ◽  
Naked Singularities ◽  
Physical Conditions ◽  
Perfect Fluids

Here we investigate the genericity and stability aspects for naked singularities and black holes that arise as the final states for a complete gravitational collapse of a spherical massive matter cloud. The form of the matter considered is a general Type I matter field, which includes most of the physically reasonable matter fields such as dust, perfect fluids and such other physically interesting forms of matter widely used in gravitation theory. Here, we first study in some detail the effects of small pressure perturbations in an otherwise pressure-free collapse scenario, and examine how a collapse evolution that was going to the black hole endstate would be modified and go to a naked singularity, once small pressures are introduced in the initial data. This allows us to understand the distribution of black holes and naked singularities in the initial data space. Collapse is examined in terms of the evolutions allowed by Einstein equations, under suitable physical conditions and as evolving from a regular initial data. We then show that both black holes and naked singularities are generic outcomes of a complete collapse, when genericity is defined in a suitable sense in an appropriate space.

scholarly journals Dilaton Black Holes, Naked Singularities and Strings

1994 ◽  
Vol 26 (5) ◽  
pp. 321-326 ◽  
Author(s):  
P. H Cox ◽  
B Harms ◽  
Y Leblanc
Keyword(s):  
Black Holes ◽  
Naked Singularities ◽  
Dilaton Black Holes

Black Holes and Naked Singularities in an Infinite Momentum Frame

2020 ◽  
Vol 75 (1) ◽  
pp. 1-9
Author(s):  
D. V. Gal’tsov ◽  
A. V. Kulitskii
Keyword(s):  
Black Holes ◽  
Naked Singularities

scholarly journals Black holes and naked singularities from Anton–Schmidt’s fluids

2020 ◽  
Vol 28 ◽  
pp. 100513 ◽  
Author(s):  
Salvatore Capozziello ◽  
Rocco D’Agostino ◽  
Daniele Gregoris
Keyword(s):  
Black Holes ◽  
Naked Singularities

scholarly journals Dynamics of Electromagnetic Fields and Structure of Regular Rotating Electrically Charged Black Holes and Solitons in Nonlinear Electrodynamics Minimally Coupled to Gravity

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 205 ◽  
Author(s):  
Irina Dymnikova ◽  
Evgeny Galaktionov
Keyword(s):  
Black Holes ◽  
Electromagnetic Fields ◽  
Nonlinear Electrodynamics ◽  
Axially Symmetric ◽  
De Sitter ◽  
Dynamical Equations ◽  
Naked Singularities ◽  
Charged Black Holes ◽  
De Sitter Vacuum ◽  
Electrically Charged

We study the dynamics of electromagnetic fields of regular rotating electrically charged black holes and solitons replacing naked singularities in nonlinear electrodynamics minimally coupled to gravity (NED-GR). They are related by electromagnetic and gravitational interactions and described by the axially symmetric NED-GR solutions asymptotically Kerr-Newman for a distant observer. Geometry is described by the metrics of the Kerr-Schild class specified by T t t = T r r ( p r = − ρ ) in the co-rotating frame. All regular axially symmetric solutions obtained from spherical solutions with the Newman-Janis algorithm belong to this class. The basic generic feature of all regular objects of this class, both electrically charged and electrically neutral, is the existence of two kinds of de Sitter vacuum interiors. We analyze the regular solutions to dynamical equations for electromagnetic fields and show which kind of a regular interior is favored by electromagnetic dynamics for NED-GR objects.

scholarly journals TYPE II FLUID SOLUTIONS TO EINSTEIN'S FIELD EQUATIONS IN N-DIMENSIONAL SPHERICAL SPACETIMES

2002 ◽  
Vol 11 (01) ◽  
pp. 113-124 ◽  
Author(s):  
JAIME F. VILLAS Da ROCHA
Keyword(s):  
Black Holes ◽  
Large Class ◽  
Type Ii ◽  
Einstein Field Equations ◽  
Spacetime Dimension ◽  
Einstein’S Field Equations ◽  
Field Equations ◽  
Self Similarity ◽  
Naked Singularities ◽  
Type Ii Fluid

A large class of Type II fluid solutions to Einstein field equations in N-dimensional spherical spacetimes is found, wich includes most of the known solutions. A family of the generalized collapsing Vaidya solutions with homothetic self-similarity, parametrized by a constant λ, is studied, and found that when λ>λ c (N), the collapse always forms black holes, and when λ<λ c (N), it always forms naked singularities, where λ c (N) is function of the spacetime dimension N only.

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