Approximate Solutions of the Einstein Equations for Isentropic Motions of Plane-Symmetric Distributions of Perfect Fluids

1957 ◽  
Vol 107 (3) ◽  
pp. 884-900 ◽  
Author(s):  
A. H. Taub

2012 ◽  
Vol 21 (08) ◽  
pp. 1250066 ◽  
Author(s):  
PANKAJ S. JOSHI ◽  
DANIELE MALAFARINA ◽  
RAVINDRA V. SARAYKAR

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.





1985 ◽  
Vol 17 (10) ◽  
pp. 1001-1013 ◽  
Author(s):  
Li jian-zeng ◽  
Liang can-bin


1987 ◽  
Vol 28 (12) ◽  
pp. 2949-2950 ◽  
Author(s):  
Sonia Berger ◽  
Roberto Hojman ◽  
Jorge Santamarina


1995 ◽  
Vol 118 (3) ◽  
pp. 511-526 ◽  
Author(s):  
Alan D. Rendall

AbstractThe existence and nature of singularities in locally spatially homogeneous solutions of the Einstein equations coupled to various phenoraenological matter models is investigated. It is shown that, under certain reasonable assumptions on the matter, there are no singularities in an expanding phase of the evolution and that unless the spacetime is empty a contracting phase always ends in a singularity where at least one scalar invariant of the curvature diverges uniformly. The class of matter models treated includes perfect fluids, mixtures of non-interacting perfect fluids and collisionless matter.



2004 ◽  
Vol 21 (22) ◽  
pp. 5043-5074 ◽  
Author(s):  
A P Barnes ◽  
P G Lefloch ◽  
B G Schmidt ◽  
J M Stewart


2016 ◽  
Vol 94 (2) ◽  
pp. 177-179
Author(s):  
L.A. López ◽  
Omar Pedraza ◽  
V.E. Ceron

We present a three-parameter time-dependent solution of the vacuum Einstein equations in five dimensions. The solution is obtained by applying the Wick rotation to the Myers–Perry solution that represents a rotating black hole in five dimensions. The new interpretation of the Myers–Perry solution can be considered among the generalized Einstein–Rosen type that can be interpreted as plane-symmetric waves, cylindrical waves or cosmological space–time in five dimensions. In some limits the solution has boost-rotational symmetry and it is asymptotically flat. In the case that the solution represents a cylindrical space–time, the E-energy is analyzed.





1994 ◽  
Vol 03 (03) ◽  
pp. 647-651 ◽  
Author(s):  
SANDIP K. CHAKRABARTI ◽  
PANKAJ S. JOSHI

Naked singularities appear naturally in dynamically evolving solutions of Einstein equations involving gravitational collapse of radiation, dust, and perfect fluids provided the rate of accretion is less than a critical value. We propose that the gamma-ray bursters (GRBs) are examples of these naked singularity solutions. For illustration, we show that according to solutions involving spherically symmetric collapse of pure radiation field, the energy Eγ and the observed duration Δt0 of a GRB should satisfy, [Formula: see text] being the fraction (10−2 to 10−3) of energy released as gamma rays and the rest possibly as gravitational waves. All the presently observed GRBs satisfy this condition; those satisfying the condition close to equality must necessarily be of cosmological origin with the red-shift factor z not exceeding ~1−10 depending on exact observed flux, red-shift and conversion efficiency of gamma rays. If GRBs are indeed from naked singular regions, they should also be accompanied by a strong burst of gravitational waves which, if detectible, will constitute a basic test for our model.



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