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In this paper, the shadows cast by non-rotating and rotating modified gravity black holes are investigated. In addition to the black hole spin parameter $a$ and the inclination angle $\theta$ of observer, another parameter $\alpha$…

General Relativity and Quantum Cosmology · Physics 2019-04-08 Hui-Min Wang , Yu-Meng Xu , Shao-Wen Wei

We present calculations for the anticipated shadow sizes of Sgr A* and the supermassive black hole in the galaxy M87 in the context of the MOG modified theory of gravity (also known as Scalar-Tensor-Vector-Gravity, or STVG). We demonstrate…

General Relativity and Quantum Cosmology · Physics 2020-01-23 J. W. Moffat , V. T. Toth

The study of astrophysical phenomena like black hole shadows is an effective approach to properly understand the modified gravity and explore its validity. Motivated by recent astrophysical observations, we consider a black hole (BH) in…

General Relativity and Quantum Cosmology · Physics 2025-03-20 Khadije Jafarzade , Zeynab Bazyar , Mubasher Jamil

The field equations for Scalar-Tensor-Vector-Gravity (STVG) or modified gravity (MOG) have a static, spherically symmetric black hole solution determined by the mass $M$ with two horizons. The strength of the gravitational constant is…

General Relativity and Quantum Cosmology · Physics 2015-05-05 J. W. Moffat

We study the strong gravitational lensing effect around rotating black holes in different gravity theories. By calculating the deflection angle of strong gravitational lensing, we evaluate the lensing observables including the image…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Xiao-Mei Kuang , Zi-Yu Tang , Bin Wang , Anzhong Wang

Higher dimensional theories admit astrophysical objects like supermassive black holes, which are rather different from standard ones, and their gravitational lensing features deviate from general relativity. It is well known that a black…

General Relativity and Quantum Cosmology · Physics 2018-05-31 Muhammed Amir , Balendra Pratap Singh , Sushant G. Ghosh

In the context of f(R) modified gravity theories we determine that the black holes existence is determined by the sign of a parameter dependent of the mass, the charge, the spin and the scalar curvature. We obtain the different…

General Relativity and Quantum Cosmology · Physics 2012-02-07 J. A. R. Cembranos , A. de la Cruz-Dombriz , P. Jimeno Romero

We study the shadows cast by near-extremal Kerr-MOG black holes for different values of the parameter in modified gravity (MOG). In particular, we consider an isotropic emitter orbiting near such black holes and analytically compute the…

General Relativity and Quantum Cosmology · Physics 2018-11-12 Minyong Guo , Niels A. Obers , Haopeng Yan

In this paper, we investigate the dynamic phenomenological signatures of a Schwarzschild-MOG black hole shadow perturbed by passing gravitational waves. By perturbing the Hamilton-Jacobi equation for photon null geodesics, we demonstrate…

General Relativity and Quantum Cosmology · Physics 2026-03-04 Nikko John Leo S. Lobos , Emmanuel T. Rodulfo

We calculate the characteristics of the "black hole shadow" for a rotating, neutral black hole in fourth-order conformal Weyl gravity. It is shown that the morphology is not significantly affected by the underlying framework, except for…

General Relativity and Quantum Cosmology · Physics 2018-04-13 Jonas R. Mureika , Gabriele U. Varieschi

A covariant modified gravity (MOG) is formulated by adding to general relativity two new degrees of freedom, a scalar field gravitational coupling strength $G= 1/\chi$ and a gravitational spin 1 vector field $\phi_\mu$. The $G$ is written…

General Relativity and Quantum Cosmology · Physics 2021-02-17 J. W. Moffat

We analyze the thermodynamical properties of black holes in a modified theory of gravity, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters without dark matter. The thermodynamics of non-rotating and…

General Relativity and Quantum Cosmology · Physics 2016-05-20 Jonas R. Mureika , John W. Moffat , Mir Faizal

Black hole shadows are a widespread topic in astrophysics. This paper searches for an optical view of the black hole and the relationship between black hole shadow and photon sphere with curvature. We were inspired by the observations of…

General Relativity and Quantum Cosmology · Physics 2025-08-26 Ajay Kumar Sharma , Kanav Ganguly , Murli Manohar Verma

Observations of the black hole shadow of supermassive black holes, such as Sagittarius A* at the center of our Milky Way galaxy, allow us to study the properties of black holes and the nature of strong-field gravity. According to the Kerr…

General Relativity and Quantum Cosmology · Physics 2018-11-14 Dimitry Ayzenberg , Nicolas Yunes

Zhang have obtained recently a twisted rotating black hole metric, which is a vacuum solution in four-dimensional Einstein gravity. This black hole solution has a rotation parameter, but without the total angular moment. Here, we have…

General Relativity and Quantum Cosmology · Physics 2016-10-21 Songbai Chen , Jiliang Jing

The shadow of a rotating black hole with nonvanishing gravitomagnetic charge has been studied. It was shown that in addition to the angular momentum of black hole the gravitomagnetic charge term deforms the shape of the black hole shadow.…

In this paper, we use a suitable conformal rescaling to construct static and rotating regular black holes in conformal massive gravity. The new metric is characterized by the mass $M$, the "scalar charge" $Q$, the angular momentum parameter…

General Relativity and Quantum Cosmology · Physics 2020-02-18 Kimet Jusufi , Mubasher Jamil , Hrishikesh Chakrabarty , Qiang Wu , Cosimo Bambi , Anzhong Wang

The static vacuum spherically symmetric solutions in massive gravity are obtained both analytically and numerically. The solutions depend on two parameters (integration constants): the mass M (or, equivalently, the Schwarzschild radius),…

General Relativity and Quantum Cosmology · Physics 2011-06-10 Michael V. Bebronne , Peter G. Tinyakov

We study the shadow of a charged rotating black hole in $f(R)$ gravity. This black hole is characterized by mass, $M$, spin, $a$, electric charge, $Q$ and $R_{0}$ which is proportional to cosmological constant. We analyze the image of the…

General Relativity and Quantum Cosmology · Physics 2022-10-06 Sara Dastan , Reza Saffari , Saheb Soroushfar

The scalar-tensor-vector gravity (STVG) theory has attracted significant interest due to its ability to effectively address the issue of galaxy rotation curves and clusters of galaxies without considering the influence of dark matter. In…

General Relativity and Quantum Cosmology · Physics 2024-09-04 Wentao Liu , Di Wu , Xiongjun Fang , Jiliang Jing , Jieci Wang
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