scholarly journals Shadow cast by a rotating and nonlinear magnetic-charged black hole in perfect fluid dark matter

2021 ◽  
pp. 2150112
Author(s):  
Tian-Chi Ma ◽  
He-Xu Zhang ◽  
Peng-Zhang He ◽  
Hao-Ran Zhang ◽  
Yuan Chen ◽  
...  
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Perfect Fluid ◽  
Emission Rate ◽  
Magnetic Charge ◽  
Spherically Symmetric ◽  
Intensity Parameter ◽  
Shadow Cast ◽  
Sgr A ◽  
Charge Formula

In this paper, we derived an exact solution of the spherically symmetric Hayward black hole surrounded by perfect fluid dark matter (PFDM). By applying the Newman–Janis algorithm, we generalized it to the corresponding rotating black hole. Then, we studied the shadows of rotating Hayward black hole in PFDM. The apparent shape of the shadow depends upon the black hole spin [Formula: see text], the magnetic charge [Formula: see text] and the PFDM intensity parameter [Formula: see text]. The shadow is a perfect circle in the non-rotating case [Formula: see text] and a deformed one in the rotating case [Formula: see text]. For a fixed value of [Formula: see text], the size of the shadow increases with the increasing [Formula: see text], but decreases with the increasing [Formula: see text]. We further investigated the black hole emission rate. We found that the emission rate decreases with the increasing [Formula: see text] (or [Formula: see text]) and the peak of the emission shifts to lower frequency. Finally, we discussed the observational prospects corresponding to the supermassive black hole Sgr A[Formula: see text] at the center of the Milky Way.

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 Shadow Images of a Rotating Dyonic Black Hole with a Global Monopole Surrounded by Perfect Fluid

Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 23 ◽  
Author(s):  
Sumarna Haroon ◽  
Kimet Jusufi ◽  
Mubasher Jamil
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Perfect Fluid ◽  
Event Horizon ◽  
Emission Rate ◽  
Surface Topology ◽  
Global Monopole ◽  
Energy Emission ◽  
Bonnet Theorem ◽  
Fluid Parameters

In this paper, we revisit the rotating global monopole metric and extend the metric to a rotating dyonic global monopole in the presence of a perfect fluid. We then show that the surface topology at the event horizon, related to the metric computed, is a 2-sphere using the Gauss-Bonnet theorem. By choosing ω = − 1 / 3 , 0 , 1 / 3 we investigate the effect of dark matter, dust and radiation on the silhouette of a black hole. The presence of the global monopole parameter γ and the perfect fluid parameters υ also deform the shape of a black hole’s shadow, which has been depicted through graphical illustrations. Finally, we analyse the energy emission rate of a rotating dyonic global monopole surrounded by perfect fluid with respect to parameters.

scholarly journals Shadow and deflection angle of charged rotating black hole surrounded by perfect fluid dark matter

2021 ◽  
Author(s):  
Farruh Atamurotov ◽  
Uma Papnoi ◽  
Kimet Jusufi
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Perfect Fluid ◽  
Deflection Angle ◽  
Graphical Representation ◽  
Null Geodesic ◽  
Rotation Parameter ◽  
Rotational Parameter ◽  
Rotating Black Hole ◽  
Shadow Cast

Abstract We analysed the shadow cast by charged rotating black hole (BH) in presence of perfect fluid dark matter (PFDM). We studied the null geodesic equations and obtained the shadow of the charged rotating BH to see the effects of PFDM parameter $\gamma$, charge $Q$ and rotation parameter $a$, and it is noticed that the size as well as the shape of BH shadow is affected due to PFDM parameter, charge and rotation parameter. Thus, it is seen that the presence of dark matter around a BH affects its spacetime. We also investigated the influence of all the parameters (PFDM parameter $\gamma$, BHs charge $Q$ and rotational parameter $a$) on effective potential, energy emission by graphical representation, and compare all the results with the non rotating case in usual general relativity. To this end, we have also explored the effect of PFDM on the deflection angle and the size of Einstein rings.

scholarly journals Dynamics of test particles around a Bardeen black hole surrounded by perfect fluid dark matter

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Bakhtiyor Narzilloev ◽  
Javlon Rayimbaev ◽  
Sanjar Shaymatov ◽  
Ahmadjon Abdujabbarov ◽  
Bobomurat Ahmedov ◽  
...  
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Perfect Fluid ◽  
Test Particles

Gravitational collapse of dark matter interacting with dark energy: Black hole formation

2017 ◽  
Vol 26 (13) ◽  
pp. 1750142 ◽  
Author(s):  
Hasrat Hussain Shah ◽  
Quaid Iqbal
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Collapse ◽  
Anisotropic Pressure ◽  
Spherically Symmetric ◽  
Hole Formation ◽  
White Hole ◽  
De Formula ◽  
Symmetric Star

In this work, we study the gravitational collapsing process of a spherically symmetric star constitute of Dark Matter (DM), [Formula: see text], and Dark Energy (DE) [Formula: see text]. In this model, we use anisotropic pressure with Equation of State (EoS) [Formula: see text] and [Formula: see text], [Formula: see text]. It reveals that gravitational collapse of DM and DE with interaction leads to the formation of the black hole. When [Formula: see text] (phantoms), dust and phantoms could be ejected from the death of white hole. This emitted matter again undergoes to collapsing process and becomes the black hole. This study gives the generalization for isotropy of pressure in the fluid to anisotropy when there will be interaction between DM and DE.

scholarly journals Dynamics and epicyclic motions of particles around the Schwarzschild–de Sitter black hole in perfect fluid dark matter

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
Javlon Rayimbaev ◽  
Sanjar Shaymatov ◽  
Mubasher Jamil
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Perfect Fluid ◽  
Matter Field ◽  
De Sitter ◽  
Circular Orbits ◽  
Test Particles ◽  
Remarkable Result ◽  
The Impact ◽  
Twin Peak

AbstractIn this paper, we investigate circular orbits for test particles around the Schwarzschild–de Sitter (dS) black hole surrounded by perfect fluid dark matter. We determine the region of circular orbits bounded by innermost and outermost stable circular orbits. We show that the impact of the perfect fluid dark matter shrinks the region where circular orbits can exist as the values of both innermost and outermost stable circular orbits decrease. We find that for specific lower and upper values of the dark matter parameter there exist double matching values for inner and outermost stable circular orbits. It turns out that the gravitational attraction due to the dark matter contribution dominates over cosmological repulsion. This gives rise to a remarkable result in the Schwarzschild–de Sitter black hole surrounded by dark matter field in contrast to the Schwarzschild–de Sitter metric. Finally, we study epicyclic motion and its frequencies with their applications to twin peak quasi-periodic oscillations (QPOs) for various models. We find the corresponding values of the black hole parameters which could best fit and explain the observed twin peak QPO object GRS 1915+109 from microquasars.

scholarly journals Testing Generalized Einstein-Cartan-Kibble-Sciama Gravity Using Weak Deflection Angle and Shadow Cast

2020 ◽  
Author(s):  
Ali Övgün ◽  
İzzet Sakallı
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Symmetric Solution ◽  
Deflection Angle ◽  
Spherically Symmetric ◽  
Plasma Medium ◽  
Asymptotically Flat ◽  
Spherically Symmetric Solution ◽  
Shadow Cast ◽  
Bonnet Theorem

In this paper, we use a new asymptotically flat and spherically symmetric solution in the generalized Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity to study the weak gravitational lensing and its shadow cast. To this end, we first compute the weak deflection angle of generalized ECKS black hole using the Gauss–Bonnet theorem in plasma medium and in vacuum. Next by using the Newman-Janis algorithm without complexification, we derive the rotating generalized ECKS black hole and in the sequel study its shadow. Then, we discuss the effect of the ECKS parameter on the shadow of the black hole and weak deflection angle. In short, the goal of this paper is to give contribution to the ECKS theory and look for evidences to understand how the ECKS parameter effects the gravitational lensing.

Optical properties of rotating Hayward-de Sitter black hole surrounded by quintessence

2021 ◽  
pp. 2150048
Author(s):  
Yuan Chen ◽  
He-Xu Zhang ◽  
Tian-Chi Ma ◽  
Jian-Bo Deng
Keyword(s):  
Black Hole ◽  
Optical Properties ◽  
Cosmological Constant ◽  
Magnetic Charge ◽  
State Parameter ◽  
De Sitter ◽  
Text Setting ◽  
Horizon Radius ◽  
Inner Horizon ◽  
Charge Formula

In this paper, we discussed optical properties of the nonlinear magnetic charged black hole surrounded by quintessence with a nonzero cosmological constant [Formula: see text]. Setting the state parameter [Formula: see text], we studied the horizons, the photon region and the shadow of this black hole. It turned out that for a fixed quintessential parameter [Formula: see text], in a certain range, with the increase of the rotation parameter [Formula: see text] and magnetic charge [Formula: see text], the inner horizon radius increases while the outer horizon radius decreases. The cosmological horizon [Formula: see text] decreases when [Formula: see text] or [Formula: see text] increases and it increases slightly when [Formula: see text] and [Formula: see text] increase. The shapes of photon region were then studied and depicted through graphical illustrations. Finally, we discussed the effects of the quintessential parameter [Formula: see text] and the cosmological constant [Formula: see text] on the shadow of this black hole with a fixed observer position in the domain of outer communication.

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