scholarly journals Naked singularities in spherically symmetric inhomogeneous Tolman-Bondi dust cloud collapse

1993 ◽  
Vol 47 (12) ◽  
pp. 5357-5369 ◽  
Author(s):  
P. S. Joshi ◽  
I. H. Dwivedi
Keyword(s):  
Dust Cloud ◽  
Spherically Symmetric ◽  
Naked Singularities

scholarly journals SPHERICALLY SYMMETRIC GRAVITATIONAL COLLAPSE OF A DUST CLOUD IN THIRD-ORDER LOVELOCK GRAVITY

2011 ◽  
Vol 20 (12) ◽  
pp. 2317-2335 ◽  
Author(s):  
KANG ZHOU ◽  
ZHAN-YING YANG ◽  
DE-CHENG ZOU ◽  
RUI-HONG YUE
Keyword(s):  
Gravitational Collapse ◽  
Dust Cloud ◽  
Cosmic Censorship ◽  
High Order ◽  
Spherically Symmetric ◽  
Lovelock Gravity ◽  
Third Order ◽  
Relativistic Case ◽  
Naked Singularities ◽  
Cosmic Censorship Hypothesis

We investigate the spherically symmetric gravitational collapse of an incoherent dust cloud by considering a LTB-type spacetime in third-order Lovelock Gravity without cosmological constant, and give three families of LTB-like solutions which separately corresponding to hyperbolic, parabolic and elliptic. Notice that the contribution of high-order curvature corrections have a profound influence on the nature of the singularity, and the global structure of spacetime changes drastically from the analogous general relativistic case. Interestingly, the presence of high order Lovelock terms leads to the formation of massive, naked and timelike singularities in the 7D spacetime, which is disallowed in general relativity. Moveover, we point out that the naked singularities in the 7D case may be gravitational weak therefore may not be a serious threat to the cosmic censorship hypothesis, while the naked singularities in the D ≥ 8 inhomogeneous collapse violate the cosmic censorship hypothesis seriously.

INHOMOGENEOUS DUST COLLAPSE WITH COSMOLOGICAL CONSTANT

2005 ◽  
Vol 14 (03n04) ◽  
pp. 707-715 ◽  
Author(s):  
S. G. GHOSH
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse ◽  
Dust Cloud ◽  
Cosmic Censorship ◽  
Space Time ◽  
De Sitter ◽  
Naked Singularities ◽  
Asymptotic Flatness ◽  
Sitter Background ◽  
Strong Curvature

We investigate the occurrence of naked singularities in the gravitational collapse of an inhomogeneous dust cloud in an expanding de Sitter background — a piece of Tolman–Bondi–de Sitter space–time. It turns out that the collapse proceed in the same way as in the Minkowski background, i.e., the strong curvature naked singularities form and thus violate the cosmic censorship conjecture. Our result unambiguously support the fact that the asymptotic flatness of space–time is not a necessary ingredient for the development of naked singularities.

scholarly journals SPHERICALLY SYMMETRIC GRAVITATIONAL COLLAPSE OF A DUST CLOUD IN EINSTEIN–GAUSS–BONNET GRAVITY

2011 ◽  
Vol 26 (28) ◽  
pp. 2135-2147 ◽  
Author(s):  
KANG ZHOU ◽  
ZHAN-YING YANG ◽  
DE-CHENG ZOU ◽  
RUI-HONG YUE
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse ◽  
Dust Cloud ◽  
Spherically Symmetric ◽  
Relativistic Case ◽  
Bonnet Gravity ◽  
Profound Influence ◽  
Dimensional Spacetime ◽  
General Relativistic ◽  
Bonnet Term

We explore the gravitational collapse of a spherically symmetric dust cloud in the Einstein–Gauss–Bonnet gravity without a cosmological constant, and obtain three families of LTB-like solutions. It is shown that the Gauss–Bonnet term has a profound influence on the nature of singularities, and the global structure of spacetime changes drastically from the analogous general relativistic case. Interestingly, the formation of a naked, massive and uncentral singularity, allowed in five-dimensional spacetime, is forbidden if D≥6. Moreover, such singularity is gravitational strong and a serious counterexample to CCH.

scholarly journals Shadows of spherically symmetric black holes and naked singularities

2018 ◽  
Vol 482 (1) ◽  
pp. 52-64 ◽  
Author(s):  
Rajibul Shaikh ◽  
Prashant Kocherlakota ◽  
Ramesh Narayan ◽  
Pankaj S Joshi
Keyword(s):  
Black Holes ◽  
Spherically Symmetric ◽  
Naked Singularities

scholarly journals GRAVITATIONAL COLLAPSE OF SPHERICALLY SYMMETRIC PERFECT FLUID WITH KINEMATIC SELF-SIMILARITY

2002 ◽  
Vol 11 (02) ◽  
pp. 155-186 ◽  
Author(s):  
C. F. C. BRANDT ◽  
L.-M. LIN ◽  
J. F. VILLAS DA ROCHA ◽  
A. Z. WANG
Keyword(s):  
Black Holes ◽  
Perfect Fluid ◽  
Gravitational Collapse ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Self Similarity ◽  
Schwarzschild Solution ◽  
Naked Singularities

Analytic spherically symmetric solutions of the Einstein field equations coupled with a perfect fluid and with self-similarities of the zeroth, first and second kinds, found recently by Benoit and Coley [Class. Quantum Grav.15, 2397 (1998)], are studied, and found that some of them represent gravitational collapse. When the solutions have self-similarity of the first (homothetic) kind, some of the solutions may represent critical collapse but in the sense that now the "critical" solution separates the collapse that forms black holes from the collapse that forms naked singularities. The formation of such black holes always starts with a mass gap, although the "critical" solution has homothetic self-similarity. The solutions with self-similarity of the zeroth and second kinds seem irrelevant to critical collapse. Yet, it is also found that the de Sitter solution is a particular case of the solutions with self-similarity of the zeroth kind, and that the Schwarzschild solution is a particular case of the solutions with self-similarity of the second kind with the index α=3/2.

NATURE OF THE SINGULARITIES IN HIGHER-DIMENSIONAL HUSAIN SPACE–TIME

2006 ◽  
Vol 15 (09) ◽  
pp. 1359-1371 ◽  
Author(s):  
K. D. PATIL ◽  
S. S. ZADE
Keyword(s):  
Gravitational Collapse ◽  
Dimensional Space ◽  
Higher Dimensions ◽  
Cosmic Censorship ◽  
Space Time ◽  
Spherically Symmetric ◽  
Naked Singularities ◽  
Higher Dimensional ◽  
Dimensional Space Time ◽  
Cosmic Censorship Hypothesis

We generalize the earlier studies on the spherically symmetric gravitational collapse in four-dimensional space–time to higher dimensions. It is found that the central singularities may be naked in higher dimensions but depend sensitively on the choices of the parameters. These naked singularities are found to be gravitationally strong that violate the cosmic censorship hypothesis.

scholarly journals GENERATING STATIC, SPHERICALLY SYMMETRIC BLACK HOLES IN LOVELOCK GRAVITY

2009 ◽  
Vol 18 (13) ◽  
pp. 2061-2082 ◽  
Author(s):  
S. HABIB MAZHARIMOUSAVI ◽  
O. GURTUG ◽  
M. HALILSOY
Keyword(s):  
Black Holes ◽  
Higher Dimensions ◽  
Matter Field ◽  
Spherically Symmetric ◽  
Lovelock Gravity ◽  
Third Order ◽  
Naked Singularities ◽  
Test Particles ◽  
Higher Dimensional ◽  
Symmetric Black Hole

We present the generalization of a known theorem to generate static, spherically symmetric black hole solutions in higher-dimensional Lovelock gravity. Particular limits such as Gauss–Bonnet (GB) and Einstein–Hilbert (EH) in any dimension N yield all the solutions known to date with an energy–momentum. In our generalization, with special emphasis on third order Lovelock gravity, we have found two different class of solutions characterized by the matter field parameter. Several particular cases are studied and properties related to asymptotic behaviors are discussed. Our general solution, which covers topological black holes as well, splits naturally into distinct classes such as Chern–Simon (CS) and Born–Infeld (BI) in higher-dimensions. The occurence of naked singularities is studied and it is found that the space–time behaves nonsingularly in the quantum-mechanical sense when it is probed with quantum test particles. The theorem is extended to cover Bertotti–Robinson (BR) type solutions in the presence of the GB parameter alone. Finally, we prove also that extension of the theorem for a scalar–tensor source of higher dimensions (N > 4) fails to work.

HIGHER DIMENSIONAL CHARGED NULL FLUID COLLAPSE AND COSMIC CENSORSHIP

2002 ◽  
Vol 11 (02) ◽  
pp. 237-244 ◽  
Author(s):  
S. G. GHOSH ◽  
R. V. SARAYKAR
Keyword(s):  
Black Holes ◽  
Energy Condition ◽  
Cosmic Censorship ◽  
Final Outcome ◽  
Spherically Symmetric ◽  
Curvature Singularity ◽  
Naked Singularities ◽  
Dimensional Spacetime ◽  
Higher Dimensional ◽  
Strong Curvature

We analyze here the spherically symmetric collapse of a charged null fluid in a higher dimensional spacetime. Both naked singularities and black holes are shown to be developing as final outcome of the collapse. A relationship between weak energy condition and occurrence of strong curvature singularity is pointed out.

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