scholarly journals Existence of Steady States of the Massless Einstein–Vlasov System Surrounding a Schwarzschild Black Hole

2021 ◽  
Author(s):  
Håkan Andréasson
Keyword(s):  
Black Hole ◽  
Numerical Investigation ◽  
Compact Support ◽  
Arbitrary Number ◽  
Steady States ◽  
Spherically Symmetric ◽  
Finite Mass ◽  
Schwarzschild Black Hole ◽  
Matter System ◽  
Thick Shells

AbstractWe show that there exist steady states of the spherically symmetric massless Einstein–Vlasov system which surround a Schwarzschild black hole. The steady states are (thick) shells with finite mass and compact support. Furthermore we prove that an arbitrary number of shells, necessarily well separated, can surround the black hole. To our knowledge this is the first result of static self-gravitating solutions to any massless Einstein-matter system which surround a black hole. We also include a numerical investigation about the properties of the shells.

scholarly journals SOME REMARKS ON THE EINSTEIN AND MØLLER PSEUDOTENSORS FOR STATIC AND SPHERICALLY-SYMMETRIC CONFIGURATIONS

2008 ◽  
Vol 23 (08) ◽  
pp. 591-601 ◽  
Author(s):  
JERZY MATYJASEK
Keyword(s):  
Black Hole ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Static Systems

It is shown that for the spherically-symmetric and static systems the hypotheses posed by Yang and Radinschi and by Vagenas can be related to the particular distribution of the source. Simple proofs are given and a number of examples are discussed with the special emphasis put on the quantum corrected Schwarzschild black hole.

scholarly journals Shadow cast of noncommutative black holes in Rastall gravity

2020 ◽  
Vol 35 (20) ◽  
pp. 2050163 ◽  
Author(s):  
Ali Övgün ◽  
İzzet Sakallı ◽  
Joel Saavedra ◽  
Carlos Leiva
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Emission Rate ◽  
Model Parameters ◽  
Spherically Symmetric ◽  
Image Model ◽  
Schwarzschild Black Hole ◽  
Physical Validity ◽  
Shadow Cast ◽  
Noncommutative Parameter

We study the shadow and energy emission rate of a spherically symmetric noncommutative black hole in Rastall gravity. Depending on the model parameters, the noncommutative black hole can reduce to the Schwarzschild black hole. Since the nonvanishing noncommutative parameter affects the formation of event horizon, the visibility of the resulting shadow depends on the noncommutative parameter in Rastall gravity. The obtained sectional shadows respect the unstable circular orbit condition, which is crucial for physical validity of the black hole image model.

Black hole spectroscopy from a class of Plebański and Demiański space–times

2014 ◽  
Vol 92 (1) ◽  
pp. 46-50
Author(s):  
De-Jiang Qi
Keyword(s):  
Black Hole ◽  
Normal Modes ◽  
Kerr Black Hole ◽  
Black Hole Thermodynamics ◽  
Area Spectrum ◽  
Spherically Symmetric ◽  
Adiabatic Invariance ◽  
Schwarzschild Black Hole ◽  
Gravity System ◽  
Area Spectra

Recently, via adiabatic invariance, Majhi and Vagenas quantized the horizon area of the general class of a static spherically symmetric space–time. Very recently, applying the period of the gravity system with respect to the Euclidean time, Zeng and Liu derived area spectra of a Schwarzschild black hole and a Kerr black hole. It is noteworthy that the preceding methods are not useful for the quasi-normal modes. In this paper, based on those works, and as a further study, adopting near horizon approximation, applying the laws of black hole thermodynamics, we would like to investigate the black hole spectroscopy from a class of Plebański and Demiański space–times by using two different methods. The result shows that the area spectrum of the black hole is [Formula: see text], which confirms the initial proposal of Bekenstein, and the result is consistent with that already obtained by Maggiore with quasi-normal modes.

scholarly journals Observing shadow of the Schwarzschild black hole in presence of a plasma

2016 ◽  
Vol 12 (S324) ◽  
pp. 351-352 ◽  
Author(s):  
Farruh Atamurotov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Radiation ◽  
Power Law ◽  
Density Profile ◽  
Particle Motion ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Plasma Environment ◽  
Symmetric Black Hole

AbstractWe have investigated particle motion around Schwarzschild black holes in the presence of a plasma with radial power-law density profile has been shown that the photon sphere around a spherically symmetric black hole is unchanged under the influence of the plasma; however, the Schwarzschild black hole shadow size is reduced due to the refraction of electromagnetic radiation in the plasma environment of the black hole.

scholarly journals Hawking Radiation for Non-Minimally Coupled Matter from Generalized 2-D Black Hole Models

1997 ◽  
Vol 12 (35) ◽  
pp. 2683-2689 ◽  
Author(s):  
W. Kummer ◽  
H. Liebl ◽  
D. V. Vassilevich
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Hawking Radiation ◽  
Scalar Fields ◽  
Global Structure ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Minimal Coupling ◽  
Scalar Matter ◽  
Inherent Ambiguity

It is well known that spherically symmetric reduction of general relativity (SSG) leads to non-minimally coupled scalar matter. We generalize (and correct) recent results to Hawking radiation for a class of dilaton models which share with the Schwarzschild black hole non-minimal coupling of scalar fields and the basic global structure. An inherent ambiguity of such models (if they differ from SSG) is discussed. However, for SSG we obtain the rather disquieting result of a negative Hawking flux at infinity, if the usual recipe for such calculations is applied.

scholarly journals Accretion onto a noncommutative-inspired Schwarzschild black hole

2018 ◽  
Vol 33 (14n15) ◽  
pp. 1850084 ◽  
Author(s):  
Sunandan Gangopadhyay ◽  
Biplab Paik ◽  
Rituparna Mandal
Keyword(s):  
Black Hole ◽  
Steady State ◽  
Sound Speed ◽  
Accretion Rate ◽  
Thermal Environment ◽  
Spherically Symmetric ◽  
Baryonic Matter ◽  
Schwarzschild Black Hole ◽  
Sonic Point ◽  
Fundamental Equations

In this paper, we investigate the problem of ordinary baryonic matter accretion onto the noncommutative (NC) geometry-inspired Schwarzschild black hole. The fundamental equations governing the spherically symmetric steady state matter accretion are deduced. These equations are seen to be modified due to the presence of noncommutativity. The matter accretion rate is computed and is found to increase rapidly with the increase in strength of the NC parameter. The sonic radius reduces while the sound speed at the sonic point increases with the increase in the strength of noncommutativity. The profile of the thermal environment is finally investigated below the sonic radius and at the event horizon and is found to be affected by noncommutativity.

scholarly journals THERMODYNAMICS OF HORIZONS: A COMPARISON OF SCHWARZSCHILD, RINDLER AND de SITTER SPACETIMES

2002 ◽  
Vol 17 (15n17) ◽  
pp. 923-942 ◽  
Author(s):  
T. PADMANABHAN
Keyword(s):  
Black Hole ◽  
Vacuum State ◽  
Quantum States ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Black Hole Spacetimes ◽  
Conformal Field ◽  
Symmetric Spacetimes ◽  
Transverse Area

The notions of temperature, entropy and 'evaporation', usually associated with spacetimes with horizons, are analyzed using general approach and the following results, applicable to different spacetimes, are obtained at one go. (i) The concept of temperature associated with the horizon is derived in a unified manner and is shown to arise from purely kinematic considerations. (ii) QFT near any horizon is mapped to a conformal field theory without introducing concepts from string theory. (iii) For spherically symmetric spacetimes (in D = 1 + 3) with a horizon at r = l, the partition function has the generic form Z ∝ exp [S - βE], where S = (1/4)4πl2 and |E| = (l/2). This analysis reproduces the conventional result for the black hole spacetimes and provides a simple and consistent interpretation of entropy and energy E = - (1/2)H-1 for deSitter spacetime. The classical Einstein's equations for this spacetime can be expressed as a thermodynamic identity, TdS - dE = PdV with the same variables. (iv) For the Rindler spacetime the entropy per unit transverse area turns out to be (1/4) while the energy is zero. (v) In the case of a Schwarzschild black hole there exist quantum states (like Unruh vacuum) which are not invariant under time reversal and can describe black hole evaporation. There also exist quantum states (like Hartle-Hawking vacuum) in which temperature is well-defined but there is no flow of radiation to infinity. In the case of deSitter universe or Rindler patch in flat spacetime, one usually uses quantum states analogous to Hartle-Hawking vacuum and obtains a temperature without the corresponding notion of evaporation. It is, however, possible to construct the analogues of Unruh vacuum state in the other cases as well. The implications are briefly discussed.

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