OF CHARGED STARS AND CHARGED BLACK HOLES

2004 ◽  
Vol 13 (07) ◽  
pp. 1375-1379 ◽  
Author(s):  
MANUEL MALHEIRO ◽  
RODRIGO PICANÇO ◽  
SUBHARTHI RAY ◽  
JOSÉ P. S. LEMOS ◽  
VILSON T. ZANCHIN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Charged Particle ◽  
Equation Of State ◽  
Mass Density ◽  
Compact Star ◽  
Maximum Amount ◽  
Stellar Structure ◽  
Charged Black Holes ◽  
Polytropic Equation

Effect of maximum amount of charge a compact star can hold, is studied here. We analyze the different features in the renewed stellar structure and discuss the reasons why such huge charge is possible inside a compact star. We studied a particular case of a polytropic equation of state (EOS) assuming the charge density is proportional to the mass density. Although the global balance of force allows a huge charge, the electric repulsion faced by each charged particle forces it to leave the star, resulting in the secondary collapse of the system to form a charged black hole.

scholarly journals General stationary charged black holes as charged particle accelerators

2011 ◽  
Vol 84 (4) ◽  
Author(s):  
Yi Zhu ◽  
Shao-Feng Wu ◽  
Yu-Xiao Liu ◽  
Ying Jiang
Keyword(s):  
Black Holes ◽  
Charged Particle ◽  
Particle Accelerators ◽  
Charged Black Holes

scholarly journals Self-Regular Black Holes Quantized by means of an Analogue to Hydrogen Atoms

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chang Liu ◽  
Yan-Gang Miao ◽  
Yu-Mei Wu ◽  
Yu-Hao Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Density ◽  
Hydrogen Atoms ◽  
Quantum Black Hole ◽  
Extreme Black Hole ◽  
Angular Momenta ◽  
Probability Densities ◽  
Hoop Conjecture ◽  
Hole Model

We suggest a quantum black hole model that is based on an analogue to hydrogen atoms. A self-regular Schwarzschild-AdS black hole is investigated, where the mass density of the extreme black hole is given by the probability density of the ground state of hydrogen atoms and the mass densities of nonextreme black holes are given by the probability densities of excited states with no angular momenta. Such an analogue is inclined to adopt quantization of black hole horizons. In this way, the total mass of black holes is quantized. Furthermore, the quantum hoop conjecture and the Correspondence Principle are discussed.

Chiral asymmetries in near-horizon region of charged black hole and teleparallelism

2021 ◽  
pp. 2150073
Author(s):  
L. C. Garcia de Andrade
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Magnetic Monopoles ◽  
Charged Black Hole ◽  
Kerr Spacetime ◽  
Charged Black Holes ◽  
Physical Information ◽  
Quantum Anomalies ◽  
Spacetime Metric

The issue of encoding physical information into metric structure of physical theories has been discussed recently by the author in the case of black hole teleparallelism. In this paper, one obtains a teleparallel chiral currents from quantum anomalies and topological torsional invariants of Nieh-Yan type. The Pontryagin index is also obtained in the case of rotating Kerr spacetime metric of non-static black holes. Magnetic monopoles which appears in this approach can be eliminated by a torsion constraint. These ideas are applied to Kerr and Kerr–Newmann charged black holes.

scholarly journals Framework for generalized polytropes with complexity factor

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
Shiraz Khan ◽  
S. A. Mardan ◽  
M. A. Rehman
Keyword(s):  
Equation Of State ◽  
Energy Density ◽  
Differential Equations ◽  
Spherical Symmetry ◽  
Mass Density ◽  
Fluid Distribution ◽  
System Of Differential Equations ◽  
Systems Of Differential Equations ◽  
Polytropic Equation

AbstractA framework is developed for generalized polytropes with the help of complexity factor introduced by Herrera (Phy Rev D 97:044010, 2018), by using the spherical symmetry with anisotropic inner fluid distribution. For this purpose generalized polytropic equation of state will be used, having two cases (i) for mass density $$(\mu _{o})$$(μo), (ii) for energy density $$(\mu )$$(μ), each case leads to a system of differential equations. These systems of differential equations involve two equations with three unknowns and they will be made consistent by using the complexity factor. The analysis of the solutions of these systems will be carried out graphically by using different parametric values involved in the systems.

scholarly journals Extracting equation of state parameters from black hole-neutron star mergers: Aligned-spin black holes and a preliminary waveform model

2014 ◽  
Vol 89 (4) ◽  
Author(s):  
Benjamin D. Lackey ◽  
Koutarou Kyutoku ◽  
Masaru Shibata ◽  
Patrick R. Brady ◽  
John L. Friedman
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Equation Of State

scholarly journals CHARGED ROTATING BLACK HOLES IN DILATON GRAVITY

2007 ◽  
Vol 22 (26) ◽  
pp. 4849-4858 ◽  
Author(s):  
A. SHEYKHI ◽  
N. RIAZI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Dilaton Field ◽  
Dilaton Gravity ◽  
Charged Black Holes ◽  
Static Solutions ◽  
Rotating Black Holes ◽  
Small Rotation ◽  
Type Potential

We consider charged black holes with curved horizons, in five-dimensional dilaton gravity in the presence of Liouville-type potential for the dilaton field. We show how, by solving a pair of coupled differential equations, infinitesimally small angular momentum can be added to these static solutions to obtain charged rotating dilaton black hole solutions. In the absence of dilaton field, the nonrotating version of the solution reduces to the five-dimensional Reissner–Nordström black hole, and the rotating version reproduces the five-dimensional Kerr–Newman modification thereof for small rotation parameter. We also compute the angular momentum and the angular velocity of these rotating black holes which appear at the first order.

scholarly journals The Multiwavelength AGN Population and the X-ray Background

2013 ◽  
Vol 9 (S304) ◽  
pp. 188-194
Author(s):  
Ezequiel Treister ◽  
Claudia M. Urry ◽  
Kevin Schawinski ◽  
Brooke D. Simmons ◽  
Priyamvada Natarajan ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Density ◽  
Large Fraction ◽  
Supermassive Black Holes ◽  
X Rays ◽  
X Ray ◽  
Black Hole Growth ◽  
Hole Growth ◽  
X Ray Background

AbstractIn order to fully understand galaxy formation we need to know when in the cosmic history are supermassive black holes (SMBHs) growing more intensively, in what type of galaxies this growth is happening and what fraction of these sources are invisible at most wavelengths due to obscuration. Active Galactic Nuclei (AGN) population synthesis models that can explain the spectral shape and intensity of the cosmic X-ray background (CXRB) indicate that most of the SMBH growth occurs in moderate-luminosity (LX~ 1044 erg/s) sources (Seyfert-type AGN), at z~ 0.5−1 and in heavily obscured but Compton-thin, NH~ 1023cm−2, systems. However, this is not the complete history, as a large fraction of black hole growth does not emit significantly in X-rays either due to obscuration, intrinsic low luminosities or large distances. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, 22%, occurs in heavily-obscured systems that are not individually detected in even the deepest X-ray observations. We further investigate the AGN triggering mechanism as a function of bolometric luminosity, finding evidence for a strong connection between significant black hole growth events and major galaxy mergers from z~ 0 to z~ 3, while less spectacular but longer accretion episodes are most likely due to other (stochastic) processes. AGN activity triggered by major galaxies is responsible for ~60% of the total black hole growth. Finally, we constrain the total accreted mass density in supermassive black holes at z > 6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. We estimate an accreted mass density <1000 M⊙Mpc−3 at z~ 6, significantly lower than the previous predictions from some existing models of early black hole growth and earlier prior observations.

Rλ3-inspired black holes

2017 ◽  
Vol 32 (25) ◽  
pp. 1750130 ◽  
Author(s):  
Samuel Kováčik
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Mass Density ◽  
Hawking Temperature ◽  
Event Horizons ◽  
Microscopic Scale ◽  
Three Space

We study a black hole with a blurred mass density instead of a singular one, which is caused by the noncommutativity of three-space. Depending on its mass, such object has either none, one or two event horizons. It possesses properties, which become important on a microscopic scale, in particular, the Hawking temperature does not increase indefinitely as the mass goes to zero, but vanishes instead. Such frozen and extremely dense pieces of matter are good dark matter candidates.

scholarly journals THERMODYNAMICS IN BLACK-HOLE/CFT CORRESPONDENCE

2013 ◽  
Vol 22 (12) ◽  
pp. 1342012 ◽  
Author(s):  
BIN CHEN ◽  
JIA-JU ZHANG
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Black Hole ◽  
Two Dimensional ◽  
Charged Black Holes ◽  
Conformal Field ◽  
Inner Horizon ◽  
Holographic Description ◽  
Area Law ◽  
Lower Dimensional

The area law of Bekenstein–Hawking entropy of the black hole suggests that the black hole should have a lower-dimensional holographic description. It has been found recently that a large class of rotating and charged black holes could be holographically described a two-dimensional (2D) conformal field theory (CFT). We show that the universal information of the dual CFT, including the central charges and the temperatures, is fully encoded in the thermodynamics laws of both outer and inner horizons. These laws, characterizing how the black hole responds under the perturbation, allows us to read different dual pictures with respect to different kinds of perturbations. The remarkable effectiveness of this thermodynamics method suggest that the inner horizon could play a key role in the study of holographic description of the black hole.

scholarly journals ENTROPY OF EXTREMAL DYONIC BLACK HOLES

1996 ◽  
Vol 11 (37) ◽  
pp. 2933-2939 ◽  
Author(s):  
A. GHOSH ◽  
P. MITRA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
String Theory ◽  
Extremal Black Hole ◽  
Classical Action ◽  
Charged Black Holes ◽  
Thermodynamic Entropy ◽  
Black Hole Solutions

For extremal charged black holes, the thermodynamic entropy is proportional to the mass or charges but not proportional to the area. This is demonstrated here for dyonic extremal black hole solutions of string theory. It is pointed out that these solutions have zero classical action although the area is nonzero. By combining the general form of the entropy allowed by thermodynamics with recent observations in the literature it is possible to fix the entropy almost completely.

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