Black Holes and Trapped Surfaces

2010 ◽  
Author(s):  
José M. M. Senovilla ◽  
Alfredo Macias ◽  
Marco Maceda
Keyword(s):  
Black Holes ◽  
Trapped Surfaces

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.

scholarly journals On the Trapped Surface Characterization of the Black Hole Region in Kerr Spacetime

2018 ◽  
Vol 10 (4) ◽  
pp. 24
Author(s):  
Mohammed Kumah ◽  
Francis Oduro
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Surface Characterization ◽  
Local Approach ◽  
Kerr Spacetime ◽  
Trapped Surfaces ◽  
Trapped Surface ◽  
Future Direction

Black holes are classically characterized by event horizon which is the boundary of the region from which particles or photons can escape to infinity in the future direction. Unfortunately this characterization is a global concept as the knowledge of the whole spacetime is needed in order to locate a black hole region and the event horizon. It is therefore important to recognize black holes locally; this has motivated the need to use local approach to characterize black holes. Specifically, we apply covariant divergence and Gauss’s divergence theorems to compute the divergences and the fluxes of appropriate null vectors in the Kerr spacetime to actually determine the existence of trapped and marginally trapped surfaces in its black hole region.

scholarly journals On the Trapped Surface Characterization of Black Hole Region in Vaidya Spacetime

2018 ◽  
Vol 10 (1) ◽  
pp. 59
Author(s):  
Mohammed Kumah ◽  
Francis T. Oduro
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Surface Characterization ◽  
Local Approach ◽  
Null Infinity ◽  
Trapped Surfaces ◽  
Marginally Trapped Surfaces ◽  
Trapped Surface

Characterizing black holes by means of classical event horizon is a global concept because it depends on future null infinity. This means, to find black hole region and event horizon requires the notion of the entire spacetime which is a teleological concept. With this as a motivation, we use local approach as a complementary means of characterizing black holes. In this paper we apply Gauss divergence and covariant divergence theorems to compute the fluxes and the divergences of the appropriate null vectors in Vaidya spacetime and thus explicitly determine the existence of trapped and marginally trapped surfaces in its black hole region.

scholarly journals Formation of dynamically transversely trapping surfaces and the stretched hoop conjecture

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Hirotaka Yoshino ◽  
Keisuke Izumi ◽  
Tetsuya Shiromizu ◽  
Yoshimune Tomikawa
Keyword(s):  
Black Holes ◽  
Initial Data ◽  
Apparent Horizon ◽  
Ring System ◽  
Conformally Flat ◽  
Trapped Surfaces ◽  
Marginally Trapped Surface ◽  
Spherical Topology ◽  
Hoop Conjecture ◽  
Trapped Surface

Abstract A dynamically transversely trapping surface (DTTS) is a new concept for an extension of a photon sphere that appropriately represents a strong gravity region and has close analogy with a trapped surface. We study formation of a marginally DTTS in time-symmetric, conformally flat initial data with two black holes, with a spindle-shaped source, and with a ring-shaped source, and clarify that $\mathcal{C}\lesssim 6\pi GM$ describes the condition for the DTTS formation well, where $\mathcal{C}$ is the circumference and $M$ is the mass of the system. This indicates that an understanding analogous to the hoop conjecture for the horizon formation is possible. Exploring the ring system further, we find configurations where a marginally DTTS with the torus topology forms inside a marginally DTTS with the spherical topology, without being hidden by an apparent horizon. There also exist configurations where a marginally trapped surface with the torus topology forms inside a marginally trapped surface with the spherical topology, showing a further similarity between DTTSs and trapped surfaces.

scholarly journals The fate of Schwarzschild–de Sitter black holes in f(R) gravity

2016 ◽  
Vol 31 (09) ◽  
pp. 1650054 ◽  
Author(s):  
Andrea Addazi ◽  
Salvatore Capozziello
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Thermal Radiation ◽  
Black Hole Physics ◽  
Black Hole Horizon ◽  
De Sitter ◽  
Trapped Surfaces ◽  
Emission Time ◽  
Marginally Trapped Surfaces

The semiclassical effects of anti-evaporating black holes can be discussed in the framework of f(R) gravity. In particular, the Bousso–Hawking–Nojiri–Odinstov anti-evaporation instability of degenerate Schwarzschild–de Sitter black holes (the so-called Nariai spacetime) leads to a dynamical increasing of black hole horizon in f(R) gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces (TS) become space-like surfaces before the effective Bekenstein–Hawking emission time. As a consequence, Bousso–Hawking thermal radiation cannot be emitted in an anti-evaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.

scholarly journals Trapped surfaces in Oppenheimer-Snyder black holes

2013 ◽  
Vol 88 (6) ◽  
Author(s):  
Ingemar Bengtsson ◽  
Emma Jakobsson ◽  
José M. M. Senovilla
Keyword(s):  
Black Holes ◽  
Trapped Surfaces

THE MASS OF THE OPPENHEIMER–SNYDER-BLACK HOLE: ONLY FINITE MASS QUASI-BLACK HOLES

2013 ◽  
Vol 22 (09) ◽  
pp. 1350054 ◽  
Author(s):  
ABHAS MITRA ◽  
K. K. SINGH
Keyword(s):  
Black Holes ◽  
Proper Time ◽  
Matter Density ◽  
Gravitational Mass ◽  
Logarithmic Function ◽  
Mass Energy ◽  
Finite Mass ◽  
Final State ◽  
Trapped Surfaces ◽  
Outermost Surface

Oppenheimer and Snyder (OS) in their paper apparently showed the formation of an event horizon [see Eq. (37) in Phys. Rev.56 (1939) 455] for a collapsing homogeneous dust ball of mass M as the circumference radius of the outermost surface, rb → r0 = 2GM/c2 in a proper time [Formula: see text] in the limit of large Schwarzschild time t → ∞. But Eq. (37) was approximated from Eq. (36) whose essential character is ([Formula: see text]) where, at the boundary of the star y = rb/r0 = rbc2/2GM. And since the argument of a logarithmic function cannot be negative, one must have y ≥ 1 or 2GM/rbc2 ≤ 1. This shows that, at least, in this case (i) trapped surfaces are not formed, (ii) if the collapse indeed proceeds upto r = 0, we must have M = 0, and (iii) proper time taken for collapse τ → ∞. Thus, the gravitational mass of OS-black holes (OS-BHs), is unique and equal to zero. In fact, by invoking Birkhoff's theorem, it has been found that the OS collapse is only a fictitious mathematical artifact because it corresponds to a matter density ρ = 0 [Mitra, Astrophys. Space Sci.332 (2011) 43, arXiv:1101.0601]. Further, this is also in agreement with the proof that Schwarzschild BHs have the unique gravitational mass M = 0 [Mitra, J. Math. Phys.50 (2009), arXiv:0904.4754], and they represent asymptotic final state of physical collapse for which entire mass-energy is radiated out [Mitra and Glendenning, Mon. Not. R. Astron. Soc. Lett.404 (2010) L50, arXiv:1003.3518]. Finally this is in agreement with the conclusion that "the discussion of physical behavior of black holes, classical or quantum, is only of academic interest — we wonder whether nature allows gravitational collapse to continue inside the EH at all" [Narlikar and Padmanabhan, Found. Phys.18 (1989) 659, doi:10.1007/BF00734568].

scholarly journals TRAPPED SURFACES

2011 ◽  
Vol 20 (11) ◽  
pp. 2139-2168 ◽  
Author(s):  
JOSÉ M. M. SENOVILLA
Keyword(s):  
Black Holes ◽  
Vector Fields ◽  
Trapped Surfaces ◽  
The Core ◽  
Global Properties ◽  
Definition Of ◽  
Trapping Horizons

I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are discussed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance discussed.

scholarly journals GAMMA-RAY BURSTS AS THE BIRTH-CRIES OF BLACK HOLES

2000 ◽  
Vol 15 (15) ◽  
pp. 991-995 ◽  
Author(s):  
PANKAJ S. JOSHI ◽  
NARESH K. DADHICH ◽  
ROY MAARTENS
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gamma Ray ◽  
Massive Stars ◽  
Relativistic Effects ◽  
Gamma Ray Bursts ◽  
Trapped Surfaces ◽  
General Relativistic

The origin of cosmic gamma-ray bursts remains one of the most intriguing puzzles in astronomy. We suggest that purely general relativistic effects in the collapse of massive stars could account for these bursts. The late formation of closed trapped surfaces can occur naturally, allowing the escape of huge energy from curvature-generated fireballs, before these are hidden within a black hole.

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