scholarly journals Marginally trapped surfaces in spherical gravitational collapse

2020 ◽  
Vol 102 (6) ◽  
Author(s):  
Ayan Chatterjee ◽  
Amit Ghosh ◽  
Suresh C. Jaryal
Keyword(s):  
Gravitational Collapse ◽  
Trapped Surfaces ◽  
Marginally Trapped Surfaces

Marginally trapped surfaces in null normal foliation spacetimes: A one step generalization of LRS II spacetimes

2020 ◽  
Vol 17 (07) ◽  
pp. 2050097
Author(s):  
Abbas Sherif ◽  
Rituparno Goswami ◽  
Sunil D. Maharaj
Keyword(s):  
Stability Analysis ◽  
Gravitational Collapse ◽  
Covariant Formalism ◽  
Geometrical Properties ◽  
Trapped Surfaces ◽  
Dimensional Spacetime ◽  
One Step ◽  
Marginally Trapped Surfaces

In this paper, we study geometrical properties of marginally trapped surfaces in gravitational collapse, using a semi-tetrad covariant formalism, that provides a set of geometrical and matter variables. We first define a generalization (in a sense to be specified in the introduction) of LRS II spacetime — which we call NNF spacetimes — and show that the marginally trapped surfaces in NNF spacetimes (and the 3-surfaces they foliate) are topologically equivalently those of LRS II spacetimes. We then study the evolution of MTTs (3-surfaces foliated by marginally trapped surfaces), extending earlier work on LRS II spacetimes to NNF spacetimes, and in general any 4-dimensional spacetime. In addition, we perform a stability analysis for the marginally trapped surfaces in this formalism, using simple spacetimes as examples to demonstrate the applicability of our approach.

DOES PRESSURE ACCENTUATE GENERAL RELATIVISTIC GRAVITATIONAL COLLAPSE AND FORMATION OF TRAPPED SURFACES?

2013 ◽  
Vol 22 (05) ◽  
pp. 1350021 ◽  
Author(s):  
ABHAS MITRA
Keyword(s):  
General Relativity ◽  
Gravitational Collapse ◽  
Fluid Pressure ◽  
Free Fall ◽  
Newtonian Gravity ◽  
Tangential Pressure ◽  
Trapped Surfaces ◽  
Imperfect Fluid ◽  
Newtonian Case ◽  
General Relativistic

It is widely believed that though pressure resists gravitational collapse in Newtonian gravity, it aids the same in general relativity (GR) so that GR collapse should eventually be similar to the monotonous free fall case. But we show that, even in the context of radiationless adiabatic collapse of a perfect fluid, pressure tends to resist GR collapse in a manner which is more pronounced than the corresponding Newtonian case and formation of trapped surfaces is inhibited. In fact there are many works which show such collapse to rebound or become oscillatory implying a tug of war between attractive gravity and repulsive pressure gradient. Furthermore, for an imperfect fluid, the resistive effect of pressure could be significant due to likely dramatic increase of tangential pressure beyond the "photon sphere." Indeed, with inclusion of tangential pressure, in principle, there can be static objects with surface gravitational redshift z → ∞. Therefore, pressure can certainly oppose gravitational contraction in GR in a significant manner in contradiction to the idea of Roger Penrose that GR continued collapse must be unstoppable.

scholarly journals Cylindrically symmetric models of gravitational collapse to black holes: A short review

2015 ◽  
Vol 24 (09) ◽  
pp. 1542021 ◽  
Author(s):  
Filipe C. Mena
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Collapse ◽  
A Priori ◽  
Short Review ◽  
Gravitational Energy ◽  
Open Problems ◽  
Trapped Surfaces ◽  
Cylindrically Symmetric ◽  
Survey Results

We survey results about exact cylindrically symmetric models of gravitational collapse in General Relativity. We focus on models which result from the matching of two spacetimes having collapsing interiors which develop trapped surfaces and vacuum exteriors containing gravitational waves. We collect some theorems from the literature which help to decide a priori about eventual spacetime matchings. We revise, in more detail, some toy models which include some of the main mathematical and physical issues that arise in this context, and compute the gravitational energy flux through the matching boundary of a particular collapsing region. Along the way, we point out several interesting open problems.

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