OPEN STRING IN (3+1)-DIMENSIONAL REISSNER–NORDSTRÖM BLACK HOLE

2010 ◽  
Vol 25 (15) ◽  
pp. 1233-1238 ◽  
Author(s):  
HIROMI SUZUKI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equatorial Plane ◽  
Cosmic String ◽  
Circular Orbit ◽  
Open String ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Charged Black Holes ◽  
Open Strings

Previously we investigated the Nambu–Goto string and the wiggly cosmic string in (3+1)-dimensional Schwarzschild black hole. As an extension the solutions in (3+1)-dimensional spherically symmetric charged black holes are investigated. The solution for the wiggly string exhibits open strings lying along the circular orbit in the equatorial plane outside horizon, while the Nambu–Goto string has only a point-like solution.

WIGGLY STRINGS OF RADIAL CONFIGURATION IN THE KERR BLACK HOLE

2011 ◽  
Vol 26 (26) ◽  
pp. 1933-1942 ◽  
Author(s):  
HIROMI SUZUKI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equatorial Plane ◽  
Radial Direction ◽  
Kerr Black Hole ◽  
Spherically Symmetric ◽  
Axially Symmetric ◽  
Classical Motion ◽  
Charged Black Holes ◽  
Open Strings

Previously we investigated classical motion of a string in (3+1)-dimensional spherically symmetric neutral and charged black holes. As an extension the solutions in (3+1)-dimensional axially symmetric rotating black hole are investigated. The solutions for the wiggly string exhibit open strings lying in the radial direction in the equatorial plane outside the horizon.

WIGGLY STRING SOLUTIONS IN KERR–NEWMAN BLACK HOLE

2011 ◽  
Vol 26 (16) ◽  
pp. 1221-1230 ◽  
Author(s):  
HIROMI SUZUKI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Equatorial Plane ◽  
Circular Orbit ◽  
Axially Symmetric ◽  
Rotating Black Hole ◽  
Open Strings ◽  
Newman Black Hole ◽  
Kerr Black Holes

Previously we investigated the cosmic wiggly strings in (3+1)-dimensional Schwarzschild, Reissner–Nordström and Kerr black holes. As an extension, the solutions in (3+1)-dimensional axially symmetric charged rotating black hole are investigated. The solution for the wiggly string exhibits open strings lying along the circular orbit in the equatorial plane outside horizon.

WIGGLY STRINGS OF RADIAL CONFIGURATION IN THE SCHWARZSCHILD AND REISSNER–NORDSTRÖM BLACK HOLES

2011 ◽  
Vol 26 (19) ◽  
pp. 3275-3285 ◽  
Author(s):  
HIROMI SUZUKI
Keyword(s):  
Black Holes ◽  
Equatorial Plane ◽  
Radial Direction ◽  
Spherically Symmetric ◽  
Classical Motion ◽  
Charged Black Holes ◽  
Open Strings

We study classical motion of a string in (3+1)-dimensional spherically symmetric neutral and charged black holes. The solutions for the wiggly string exhibit open strings lying in the radial direction in the equatorial plane outside the horizon.

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.

scholarly journals Photon Spheres, ISCOs, and OSCOs: Astrophysical Observables for Regular Black Holes with Asymptotically Minkowski Cores

Universe ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Thomas Berry ◽  
Alex Simpson ◽  
Matt Visser
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Circular Orbit ◽  
Schwarzschild Black Hole ◽  
Circular Orbits ◽  
Regular Black Hole ◽  
Astrophysical Interest ◽  
Regular Black Holes ◽  
Recent Advances ◽  
Classical Black Holes

Classical black holes contain a singularity at their core. This has prompted various researchers to propose a multitude of modified spacetimes that mimic the physically observable characteristics of classical black holes as best as possible, but that crucially do not contain singularities at their cores. Due to recent advances in near-horizon astronomy, the ability to observationally distinguish between a classical black hole and a potential black hole mimicker is becoming increasingly feasible. Herein, we calculate some physically observable quantities for a recently proposed regular black hole with an asymptotically Minkowski core—the radius of the photon sphere and the extremal stable timelike circular orbit (ESCO). The manner in which the photon sphere and ESCO relate to the presence (or absence) of horizons is much more complex than for the Schwarzschild black hole. We find situations in which photon spheres can approach arbitrarily close to (near extremal) horizons, situations in which some photon spheres become stable, and situations in which the locations of both photon spheres and ESCOs become multi-valued, with both ISCOs (innermost stable circular orbits) and OSCOs (outermost stable circular orbits). This provides an extremely rich phenomenology of potential astrophysical interest.

MULTI-BLACK HOLES SOLUTION WITH COSMIC STRINGS

2004 ◽  
Vol 19 (10) ◽  
pp. 1549-1557 ◽  
Author(s):  
F. ÖZDEMIR ◽  
N. ÖZDEMIR ◽  
B. T. KAYNAK
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Cosmic String ◽  
Circular Orbit ◽  
Cosmic Strings ◽  
De Sitter ◽  
Circular Orbits ◽  
Small Oscillations ◽  
String Models

Some black hole-cosmic string models such as Reissner–Nordström, RN–de Sitter, Kerr–Newman and multi-black holes with cosmic string are given. Energy and angular momentum of a timelike particle in circular orbits in multi-black hole space–time are calculated. The geodesic equations for the timelike particles for the far region of the multi-black hole sources are calculated and small oscillations around the circular orbit obtained. It is seen that the particle's orbit precesses like the Lens–Thirring effect.

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.

The Free Energy for Rotating and Charged Black Holes and Banados, Teitelboim and Zanelli Black Holes

2018 ◽  
Vol 73 (11) ◽  
pp. 1061-1073 ◽  
Author(s):  
N.A. Hussein ◽  
D.A. Eisa ◽  
T.A.S. Ibrahim
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
Black Hole ◽  
Free Energy ◽  
Quantum Correction ◽  
Kerr Black Hole ◽  
De Sitter ◽  
Schwarzschild Black Hole ◽  
Charged Black Holes ◽  
Thermodynamic Variables

AbstractThis paper aims to obtain the thermodynamic variables (temperature, thermodynamic volume, angular velocity, electrostatic potential, and heat capacity) corresponding to the Schwarzschild black hole, Reissner-Nordstrom black hole, Kerr black hole and Kerr-Newman-Anti-de Sitter black hole. We also obtained the free energy for black holes by using three different methods. We obtained the equation of state for rotating Banados, Teitelboim and Zanelli black holes. Finally, we used the quantum correction of the partition function to obtain the heat capacity and entropy in the quantum sense.

scholarly journals Effect of the inner horizon on the black hole thermodynamics: Reissner–Nordström black hole and Kerr black hole

2021 ◽  
pp. 2150177
Author(s):  
G. E. Volovik
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Kerr Black Hole ◽  
Black Hole Thermodynamics ◽  
Spherically Symmetric ◽  
Schwarzschild Black Hole ◽  
Inner Horizon ◽  
Hole Charge

For the Schwarzschild black hole, the Bekenstein–Hawking entropy is proportional to the area of the event horizon. For the black holes with two horizons, the thermodynamics is not very clear, since the role of the inner horizons is not well established. Here we calculate the entropy of the Reissner–Nordström black hole and of the Kerr black hole, which have two horizons. For the spherically symmetric Reissner–Nordström black hole, we used several different approaches. All of them give the same result for the entropy and for the corresponding temperature of the thermal Hawking radiation. The entropy is not determined by the area of the outer horizon, and it is not equal to the sum of the entropies of two horizons. It is determined by the correlations between the two horizons, due to which the total entropy of the black hole and the temperature of Hawking radiation depend only on mass M of the black hole and do not depend on the black hole charge Q. For the Kerr and Kerr–Newman black holes, it is shown that their entropy has the similar property: it depends only on mass M of the black hole and does not depend on the angular momentum J and charge Q.

scholarly journals A Smarr formula for charged black holes in nonlinear electrodynamics

2017 ◽  
Vol 32 (39) ◽  
pp. 1750219 ◽  
Author(s):  
Leonardo Balart ◽  
Sharmanthie Fernando
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
General Formula ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Nonlinear Electrodynamics ◽  
Spherically Symmetric ◽  
Charged Black Holes ◽  
Electrically Charged ◽  
Black Hole Solutions

It is well known that the Smarr formula does not hold for black holes in nonlinear electrodynamics. The main reason for this is the fact that the trace of the energy–momentum tensor for nonlinear electrodynamics does not vanish as it is for Maxwell’s electrodynamics. Starting from the Komar integral, we derived a new Smarr-type formula for spherically symmetric static electrically charged black hole solutions in nonlinear electrodynamics. We show that this general formula is in agreement with some that are obtained for black hole solutions with nonlinear electrodynamics.

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