scholarly journals Weak Deflection Angle by Casimir Wormhole Using Gauss-Bonnet Theorem and Its Shadow

2020 ◽  
Author(s):  
Wajiha Javed ◽  
Ali Hamza ◽  
Ali Övgün
Keyword(s):  
Event Horizon ◽  
Deflection Angle ◽  
Weak Limit ◽  
Plasma Medium ◽  
Spacetime Geometry ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation ◽  
Optical Metric

Here we calculate the deflection angle of photon by Casimir wormhole in weak limit approximation. First we calculate Gaussian optical curvature with the help of optical spacetime geometry and so we use the Gauss-Bonnet theorem on Gaussian optical metric and find deflection angle of photon by Casimir wormhole. Moreover, we calculate the photon's deflection angle in the presence of plasma medium and we also see the graphical nature of deflection angle in both cases. After calculating the deflection angle of Casimir wormhole. Now, we move towards the shadow of Casimir wormhole. After the observations of Event Horizon Telescope, the study of shadow become very important so that we plot the shapes of shadow of Casimir wormhole, and we calculate the photon geodesic around the Casimir wormhole.

scholarly journals Weak Deflection Angle by Casimir Wormhole Using Gauss-Bonnet Theorem and Its Shadow

2020 ◽  
Author(s):  
Wajiha Javed ◽  
Ali Hamza ◽  
Ali Övgün
Keyword(s):  
Deflection Angle ◽  
Weak Field ◽  
Plasma Medium ◽  
Field Limit ◽  
Spacetime Geometry ◽  
Weak Field Limit ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation ◽  
Optical Metric

In this paper, we calculate the deflection angle of photon by Casimir wormhole in the weak field limit approximation. First we calculate Gaussian optical curvature with the help of optical spacetime geometry and so we use the Gauss-Bonnet theorem on the Gaussian optical metric. Then we find the deflection angle of photon by Casimir wormhole. Moreover, we calculate the photon's deflection angle in the presence of plasma medium and we also see the graphical nature of deflection angle in both cases. Second, we move towards the shadow of Casimir wormhole. After the observations of Event Horizon Telescope, the study of shadow become very important so that we plot the shapes of shadow of Casimir wormhole, and we calculate the photon geodesic around the Casimir wormhole.

scholarly journals Deflection Angle of Photon from Magnetized Black Hole and Effect of Nonlinear Electrodynamics

2019 ◽  
Author(s):  
Wajiha Javed ◽  
jameela Abbas ◽  
Ali Övgün
Keyword(s):  
Black Hole ◽  
Deflection Angle ◽  
Weak Limit ◽  
Nonlinear Electrodynamics ◽  
Leading Order ◽  
Hole Charge ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation ◽  
Optical Metric

In this paper, we proposed a new model of non-linear electrodynamics with parameter. Firstly, we study the weak limit approximation and by using the Gauss Bonnet theorem, we obtain the deflection angle of photon from magnetized black hole and effect of bnon-linear electrodynamics. In doing so, we find the corresponding optical metric after that we calculate the Gaussian curvature which is used in Gauss Bonnet theorem. Then we show the deflection angle in the leading order terms. We also analyzed that our results reduces into Maxwell's electrodynamics and RN solution with the reduction of parameters. Moreover, we also investigate the graphical behavior of deflection angle w.r.t correction parameter, black hole charge and impact parameter.

scholarly journals Deflection angle of light by wormholes using the Gauss–Bonnet theorem

2017 ◽  
Vol 14 (12) ◽  
pp. 1750179 ◽  
Author(s):  
Kimet Jusufi
Keyword(s):  
Deflection Angle ◽  
Weak Limit ◽  
Space Time ◽  
Geometrical Method ◽  
Optical Geometry ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation

In this paper, we have investigated the deflection angle of light by wormholes using a new geometrical method known as Gibbons–Werner method (GW). In particular, we have calculated the deflection angle of light in the weak limit approximation in two wormhole space–time geometries: Ellis wormhole and Janis–Newman–Winnicour (JNW) wormhole. We have employed the famous Gauss–Bonnet theorem (GBT) to the Ellis wormhole optical geometry and JNW wormhole optical geometry, respectively. By using GBT, we computed the deflection angles in leading orders by these wormholes and our results were compared with the ones in the literature.

scholarly journals Effect of Non-Linear Electrodynamics on Weak Field Deflection Angle by Black Hole

2020 ◽  
Author(s):  
Wajiha Javed ◽  
Ali Hamza ◽  
Ali Övgün
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Field ◽  
Weak Limit ◽  
Spacetime Geometry ◽  
Weak Gravitational Field ◽  
Non Linear ◽  
The Deflection Angle ◽  
Bonnet Theorem

In this work, we investigate the weak deflection angle of light from exact black hole within the non-linear electrodynamics. First we calculate the Gaussian optical curvature using the optical spacetime geometry. With the help of modern geometrical way popularized by Gibbons and Werner, we examine the deflection angle of light from exact black hole. For this desire, we determine the optical Gaussian curvature and execute the Gauss-Bonnet theorem on optical metric and calculate the leading terms of deflection angle in the weak limit approximation. Furthermore, we likewise study the plasma medium's effect on weak gravitational lensing by exact black hole. Hence we expose the effect of the non-linear electrodynamics on the deflection angle in the weak gravitational field.

scholarly journals Weak Deflection Angle and Shadow by Tidal Charged Black Hole

2021 ◽  
Author(s):  
Wajiha Javed ◽  
Ali Hamza ◽  
Ali Övgün
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Deflection Angle ◽  
Weak Field ◽  
Charged Black Hole ◽  
Plasma Medium ◽  
Null Geodesics ◽  
The Deflection Angle ◽  
Bonnet Theorem

In this article, we calculate the deflection angle of tidal charged black hole (TCBH) in weak field limits. First we obtain the Gaussian optical curvature and then apply the Gauss-Bonnet theorem on it. With the help of Gibbons-Werner method, we are able to calculate the light's deflection angle by TCBH in weak field limits. After calculating the deflection angle of light, we check the graphical behavior of TCBH. Moreover, we further find the light's deflection angle in the presence of plasma medium and also check the graphical behavior in the presence of plasma medium. Moreover, we investigate the shadow of TCBH.For calculating the shadow, we first find the null geodesics around the TCBH and then find its shadow radius. We also obtain TCBH's shadow in the plasma medium. Hence, we discuss the shadow of the TCBH using the $M87^{*}$ parameters announced by the Event Horizon Telescope.

scholarly journals Light deflection by a quantum improved Kerr black hole pierced by a cosmic string

2019 ◽  
Vol 16 (08) ◽  
pp. 1950116 ◽  
Author(s):  
Kimet Jusufi ◽  
Ali Övgün
Keyword(s):  
Black Hole ◽  
Cosmic String ◽  
Quantum Correction ◽  
Deflection Angle ◽  
Kerr Black Hole ◽  
Weak Limit ◽  
Global Topology ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation

In this work, we calculate the quantum correction effects on the deflection of light in the space-time geometry of a quantum improved Kerr black hole pierced by an infinitely long cosmic string. More precisely, we calculate the deflection angle by applying the Gauss–Bonnet theorem (GBT) to the osculating optical geometries related to the quantum improved rotating black hole in the weak limit approximation. We find that the deflection angle of light is affected by the quantum effects as well as the global topology due to the presence of the cosmic string. Besides, we have managed to find the same expression for the deflection angle in leading order terms using the geodesic equations.

scholarly journals Quantum effects on the deflection of light and the Gauss–Bonnet theorem

2017 ◽  
Vol 14 (10) ◽  
pp. 1750137 ◽  
Author(s):  
Kimet Jusufi
Keyword(s):  
Deflection Angle ◽  
Weak Limit ◽  
Quantum Corrections ◽  
Leading Order ◽  
Schwarzschild Black Hole ◽  
Schwarzschild Solution ◽  
Bohmian Quantum Mechanics ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation

In this paper, we apply the Gauss–Bonnet (GB) theorem to calculate the deflection angle by a quantum-corrected Schwarzschild black hole in the weak limit approximation. In particular, we calculate the light deflection by two types of quantum-corrected black holes: the renormalization group improved Schwarzschild solution and the quantum-corrected Schwarzschild solution in Bohmian quantum mechanics. We start from the corresponding optical metrics to use then the GB theorem and calculate the Gaussian curvature in both cases. We calculate the leading terms of the deflection angle and show that quantum corrections modify the deflection angle in both solutions. Finally by performing geodesics calculations we show that GB method gives exact results in leading-order terms.

scholarly journals Bounding Greybody and Deflection Angle of Improved Schwarzschild Black Hole

2021 ◽  
Author(s):  
Wajiha Javed ◽  
Muhammad Aqib ◽  
Ali Övgün
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Graphical Analysis ◽  
Plasma Medium ◽  
Schwarzschild Black Hole ◽  
Weak Gravitational Lensing ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Optical Metric

We explore the deflection angle in the framework of improved Schwarzschild Black hole utilizing the most advance geometrical path adopted by Gibbon-Werner. To investigate deflection angle of the photon ray by weak gravitational lensing for this black hole, we derive the optical curvature and perform the application of Gauss-Bonnet theorem on the optical metric. Moreover, we study the impacts of the plasma medium in context of the weak gravitational lensing in relate to this black hole. Further, we also study the graphical analysis of the deflection angle in both the plasma and non-plasma mediums. Also, we find the rigorous bound base upon the greybody factor for improved Schwarzschild black hole. A while later, we contrast our conclusions about deflection angle with the deflection angles of Schwarzschild black hole within plasma and non-plasma mediums.

scholarly journals Effect of Aether Field on Weak Deflection Angle of Black Holes

2019 ◽  
Author(s):  
Ali Övgün ◽  
İzzet Sakallı ◽  
Joel Saavedra
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Limit ◽  
Spherically Symmetric ◽  
Light Rays ◽  
Topological Effect ◽  
The Deflection Angle ◽  
Bonnet Theorem ◽  
Limit Approximation

We study the light rays in a static and spherically symmetric gravitational field of null aether theory (NAT). To this end, we employ the Gauss-Bonnet theorem to compute the deflection angle by a NAT black hole in the weak limit approximation. Using the optical metrics of the NAT black hole, we first obtain the Gaussian curvature and then calculate the leading terms of the deflection angle. Our calculations show how gravitational lensing is affected by the NAT field. We also show once again that the bending of light stems from a global and topological effect.

scholarly journals Weak Deflection Angle of some Classes of non-linear Electrodynamics Black Holes via Gauss-Bonnet Theorem

2020 ◽  
Author(s):  
Hasan El Moumni ◽  
Karima Masmar ◽  
Ali Övgün
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Lensing ◽  
Deflection Angle ◽  
Weak Field ◽  
Leading Order ◽  
Plasma Medium ◽  
Non Linear ◽  
The Deflection Angle ◽  
Bonnet Theorem

In this paper, we study the gravitational lensing by some black hole classes within the non-linear electrodynamics in weak field limits. First, we calculate an optical geometry of the non-linear electrodynamics black hole then we use the Gauss-Bonnet theorem for finding deflection angle in weak field limits. The effect of non-linear electrodynamics on the deflection angle in leading order terms is studied. Furthermore, we discuss the effects of the plasma medium on the weak deflection angle.

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