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In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin $a$,…

General Relativity and Quantum Cosmology · Physics 2013-12-03 Shao-Wen Wei , Yu-Xiao Liu

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…

General Relativity and Quantum Cosmology · Physics 2021-10-25 Wajiha Javed , Ali Hamza , Ali Övgün

In some models dark energy is described by phantom scalar fields (scalar fields with "wrong" sign of the kinetic term in the lagrangian). In the current paper we study the effect of phantom scalar field and/or phantom electromagnetic field…

General Relativity and Quantum Cosmology · Physics 2013-05-31 Galin N. Gyulchev , Ivan Zh. Stefanov

In this paper, we calculate the weak deflection angle by Casimir wormhole and its shadow. To do so, we derive the Gaussian optical curvature and use the Gauss-Bonnet theorem. Then we find the deflection angle by Casimir wormhole in weak…

General Relativity and Quantum Cosmology · Physics 2021-01-13 Wajiha Javed , Ali Hamza , Ali Övgün

The presence of dark matter around a black hole remarkably affects its spacetime. We consider the effects of dark matter on the shadow of a new solution to the Einstein equations that describes a rotating black hole in the background of…

General Relativity and Quantum Cosmology · Physics 2019-02-12 Sumarna Haroon , Mubasher Jamil , Kimet Jusufi , Kai Lin , Robert B. Mann

The gravitational deflection of light signals restricted in the polar-axis plane of a moving Kerr-Newman (KN) black hole with a constant velocity along the polar axis is studied within the second post-Minkowskian (PM) approximation. For…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Xuan Wang , Wenbin Lin , Bo Yang , Guansheng He

In this manuscript, we provide a comprehensive study of gravitational lensing by dark compact objects predicted by a Modified Gravity (MOG) based on the Scalar-Vector-Tensor action, and the aim is to analyze new insights into the nature of…

General Relativity and Quantum Cosmology · Physics 2025-03-07 Nagina Rehman , Zoe C. S. Chan , Mubasher Jamil , Mustapha Azreg-Aïnou

Observations of black hole shadows with the Event Horizon Telescope have paved way for a novel approach to testing Einstein's theory of general relativity. Early analyses of the measured shadow put constraints on theory-agnostic parameters…

General Relativity and Quantum Cosmology · Physics 2021-08-04 Sourabh Nampalliwar , Saurabh K

In this research, we use the Gibbons-Werner method (Gauss-Bonnet theorem) on the optical geometry of a black hole and wormhole, extending the calculation of the weak gravitational lensing within the Maxwell's fish eye-like profile and dark…

General Physics · Physics 2019-05-15 Ali Övgün

We are developing a general, unified, and rigorous analytical framework for using gravitational lensing by compact objects to test different theories of gravity beyond the weak-deflection limit. In this paper we present the formalism for…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Charles R. Keeton , A. O. Petters

We study the bending of light in the space-time of black holes in four-dimensional Einstein-Gauss-Bonnet theory of gravity, recently proposed by Glavan and Lin \cite{Glavan}. Using Rindler-Ishak method, the effect of Gauss-Bonnet coupling…

General Relativity and Quantum Cosmology · Physics 2021-05-26 Mohaddese Heydari-Fard , Malihe Heydari-Fard , H. R. Sepangi

In this paper, we examine the weak deflection angle and greybody bound for magnetized regular black hole.$~$ For this purpose, we apply the Gauss-Bonnet theorem on the black hole and obtain the deflection angle in plasma and non-plasma…

General Relativity and Quantum Cosmology · Physics 2022-05-06 Wajiha Javed , Sibgha Riaz , Ali Övgün

This work deals with the scalar quasinormal modes using higher order WKB method and black hole shadow in non-minimal Einstein Yang-Mills theory. To validate the results of quasinormal modes, time domain profiles are also investigated. We…

General Relativity and Quantum Cosmology · Physics 2024-02-12 Dhruba Jyoti Gogoi , Supakchai Ponglertsakul

In this paper, we study the different properties of static spherically symmetric black hole solutions of Einstein-Bel-Robinson gravity (EBR), a modified four-dimensional theory of gravity quartic in curvature. We look at the orbit of…

General Relativity and Quantum Cosmology · Physics 2025-03-25 Seyed Naseh Sajadi , Supakchai Ponglertsakul , Dhruba Jyoti Gogoi

We explored how the Lorentz symmetry breaking parameter $\ell$ affects the Reissner-Nordst\"{o}m BH solution in the context of weak field deflection angle, and the black hole shadow. We aim to derive the general expression for the weak…

General Relativity and Quantum Cosmology · Physics 2025-03-17 Gaetano Lambiase , Reggie C. Pantig , Ali Övgün

The detailed study of the strong gravitational lensing of a Kerr black hole within Quantum Einstein Gravity (QEG) is performed. We calculate the photon sphere, the deflection angle of light, and observables on the equatorial plane under the…

General Relativity and Quantum Cosmology · Physics 2024-09-09 Chen-Hao Xie , Yu Zhang , Bo-Li Liu , Peng-Fei Duan , Yu-Li Lou

The null geodesics that describe photon orbits in the spacetime of a rotating electrically charged black hole (Kerr-Newman) are solved exactly including the contribution from the cosmological constant. We derive elegant closed form…

General Relativity and Quantum Cosmology · Physics 2015-02-27 G. V. Kraniotis

In this paper, we construct the slowly rotating case of an asymptotically flat supermassive black hole embedded in dark matter using Newman-Janis procedure. Our analysis is carried with respect to the involved parameters including the halo…

General Relativity and Quantum Cosmology · Physics 2024-01-05 A. El Balali , M. Benali , M. Oualaid

We investigate cosmology-driven modifications to Schwarzschild-like black hole spacetimes and analyze their impact on photon propagation, gravitational lensing, and shadow observation. The gravitational deflection angle is computed using…

General Relativity and Quantum Cosmology · Physics 2025-09-19 Ritesh Pandey , Shubham Kala , Amare Abebe , Hemwati Nandan , G. G. L. Nashed

In the Einstein-bumblebee gravity, the Lorentz symmetry is spontaneously broken by a vector field. In this paper, we attempt to test the Lorentz symmetry via the observation of the shadow cast by the Kerr-like black hole with or without…

General Relativity and Quantum Cosmology · Physics 2021-06-29 Hui-Min Wang , Shao-Wen Wei