Gravitational collapse of massless scalar field and cosmic censorship

1987 ◽  
Vol 36 (12) ◽  
pp. 3575-3581 ◽  
Author(s):  
Dalia S. Goldwirth ◽  
Tsvi Piran
2005 ◽  
Vol 14 (06) ◽  
pp. 1049-1061 ◽  
Author(s):  
R. CHAN ◽  
M. F. A. DA SILVA ◽  
J. F. VILLAS DA ROCHA ◽  
ANZHONG WANG

All the (2+1)-dimensional circularly symmetric solutions with kinematic self-similarity of the second kind to the Einstein-massless-scalar field equations are found and their local and global properties are studied. It is found that some of them represent gravitational collapse of a massless scalar field, in which black holes are always formed.


2016 ◽  
Vol 25 (01) ◽  
pp. 1650005 ◽  
Author(s):  
Alireza Allahyari ◽  
Javad T. Firouzjaee ◽  
Reza Mansouri

We study the time evolution of the Misner-Sharp mass and the apparent horizon for gravitational collapse of a massless scalar field in the [Formula: see text] spacetime for both cases of narrow and broad waves by numerically solving the Einstein’s equations coupled to a massless scalar field. This is done by relying on the full dynamics of the collapse including the concept of the dynamical horizon. It turns out that the Misner-Sharp mass is everywhere constant except for a rapid change across a thin shell defined by the density profile of the collapsing wave. By studying the evolution of the apparent horizon, indicating the formation of a black hole at different times we see how asymptotically an event horizon forms. The dependence of the thermalization time on the radius of the initial black hole event horizon is also studied.


2006 ◽  
Vol 15 (04) ◽  
pp. 545-557 ◽  
Author(s):  
R. CHAN ◽  
M. F. A. DA SILVA ◽  
JAIME F. VILLAS DA ROCHA

The (2+1)-dimensional geodesic circularly symmetric solutions of Einstein-massless-scalar field equations with negative cosmological constant are found and their local and global properties are studied. It is found that one of them represents gravitational collapse where black holes are always formed.


2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Xiaobao Wang ◽  
Xiaoning Wu ◽  
Sijie Gao

Abstract We construct analytical models to study the critical phenomena in gravitational collapse of the Husain-Martinez-Nunez massless scalar field. We first use the cut-and-paste technique to match the conformally flat solution ($$c=0$$c=0 ) onto an outgoing Vaidya solution. To guarantee the continuity of the metric and the extrinsic curvature, we prove that the two solutions must be joined at a null hypersurface and the metric function in Vaidya spacetime must satisfy certain constraints. We find that the mass of the black hole in the resulting spacetime takes the form $$M\propto (p-p^*)^\gamma $$M∝(p-p∗)γ, where the critical exponent $$\gamma $$γ is equal to 0.5. For the case $$c\ne 0$$c≠0, we show that the scalar field must be joined onto two pieces of Vaidya spacetimes to avoid a naked singularity. We also derive the power-law mass formula with $$\gamma =0.5$$γ=0.5. Compared with previous analytical models which were constructed from a different scalar field with continuous self-similarity, we obtain the same value of $$\gamma $$γ. However, we show that the solution with $$c\ne 0$$c≠0 is not self-similar. Therefore, we provide a rare example that a scalar field without self-similarity also possesses the features of critical collapse.


2008 ◽  
Vol 17 (11) ◽  
pp. 2143-2158 ◽  
Author(s):  
F. I. M. PEREIRA ◽  
R. CHAN

Self-similar solutions of a collapsing perfect fluid and a massless scalar field with kinematic self-similarity of the first kind in 2+1 dimensions are obtained. The local and global properties of the solutions are studied. It is found that some of them represent gravitational collapse, in which black holes are always formed, and some may be interpreted as representing cosmological models.


1991 ◽  
Vol 06 (15) ◽  
pp. 2693-2706 ◽  
Author(s):  
J. GREENSITE

Some issues in the quantum mechanics of gravitational collapse are discussed in the framework of a simple minisuperspace model, consisting of a Friedman metric coupled to a massless scalar field. The model illustrates the role of intrinsic time coordinates in parametrizing gravitational collapse through a singularity, and the relevance of quantizing the metric scale factor over an infinite, rather than half-infinite, range.


2003 ◽  
Vol 12 (05) ◽  
pp. 791-799
Author(s):  
G. OLIVEIRA-NETO

We study an analytical solution to the Einstein's equations in (2+1)-dimensions, representing the self-similar collapse of a circularly symmetric, minimally coupled, massless, scalar field. Depending on the value of certain parameters, this solution represents the formation of naked singularities. Since our solution is asymptotically flat, these naked singularities may be relevant for the weak cosmic censorship conjecture in (2+1)-dimensions.


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