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Related papers: Breathing Black Hole Shadows in Modified Gravity (…

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Scalar-tensor-vector gravity, also known as modified gravity (MOG), has emerged as an alternative to General Relativity (GR). It aims to explain astrophysical phenomena without invoking dark matter. The S-stars orbiting the supermassive…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Ioannis Liodis , Gernot Heissel , Rita Mastroioanni , Jai Grover , Dario Izzo

Dynamical Chern-Simons gravity is an extension of General Relativity in which the gravitational field is coupled to a scalar field through a parity-violating Chern-Simons term. In this framework, we study perturbations of spherically…

General Relativity and Quantum Cosmology · Physics 2013-12-04 C. Molina , Paolo Pani , Vitor Cardoso , Leonardo Gualtieri

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

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

In this paper we have examined spherical accretion onto Schwarzschild MOG Black Holes within the framework of Modified Gravity. Using isothermal test fluids, we analyze the behavior of the flow near the critical (sonic) point for various…

General Relativity and Quantum Cosmology · Physics 2025-10-31 Ayyesha K. Ahmed , M Z A Moughal

The Quasinormal modes (QNMs) for gravitational and electromagnetic perturbations are calculated in a Scalar-Tensor-Vector (Modified Gravity) spacetime, which was initially proposed to obtain correct dynamics of galaxies and galaxy clusters…

General Relativity and Quantum Cosmology · Physics 2018-04-18 Luciano Manfredi , Jonas Mureika , John Moffat

Based on the scalar-tensor-vector modified gravitational theory, a modified gravity Schwarzschild black hole solution has been given in the existing literature. Such a black hole spacetime is obtained through the inclusion of a modified…

General Relativity and Quantum Cosmology · Physics 2022-06-10 Daqi Yang , Wenfu Cao , Naying Zhou , Hongxing Zhang , Wenfang Liu , Xin Wu

During the glorious success of the EHT in providing the first image of a black hole, numerous papers have been published about the effect of different astrophysical environments on black hole geometry. Motivated by the work on how…

General Relativity and Quantum Cosmology · Physics 2023-12-08 Reggie C. Pantig

We have studied the shadows of a Schwarzschild black hole under a special polar gravitational perturbation, which is a particular solution of Einstein equations expanded up to first order. It is shown that the black hole shadow changes…

General Relativity and Quantum Cosmology · Physics 2022-12-12 Mingzhi Wang , Songbai Chen , Jiliang Jing

We present a comprehensive theoretical investigation of a novel black hole (BH) spacetime: a Schwarzschild BH embedded in a Hernquist-type dark matter halo (HDMH) and surrounded by a cloud of cosmic strings (CSs) -- collectively termed the…

General Relativity and Quantum Cosmology · Physics 2025-06-24 Faizuddin Ahmed , Ahmad Al-Badawi , İzzet Sakallı

We investigate particle motion in regular and asymptotically flat black hole spacetimes supported by Dehnen-type dark-matter halos. Two analytic models are analyzed, allowing a systematic study of circular geodesics, photon-sphere…

General Relativity and Quantum Cosmology · Physics 2026-03-25 Bekir Can Lütfüoğlu

In this paper, we present a black hole solution with a cosmological constant in the Scalar-Tensor-Vector Modified Gravity (MOG) theory, where the strength of the gravitational constant is determined by $G = G_\text{N}(1+\alpha)$. We derive…

General Relativity and Quantum Cosmology · Physics 2024-02-22 Wentao Liu , Xiongjun Fang , Jiliang Jing , Jieci Wang

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

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

The purpose of this study is to investigate the quasinormal modes (QNMs), greybody factors (GFs) and shadows in a plasma of a black hole (BH) surrounded by an exotic fluid of quintessence type in a scalar-vector-tensor modified gravity. The…

General Relativity and Quantum Cosmology · Physics 2024-05-21 Ahmad Al-Badawi

Can the observation of the "shadow" allow us to distinguish a black hole from a more exotic compact object? We study the motion of photons in a class of vacuum static axially-symmetric space-times that is continuously linked to the…

General Relativity and Quantum Cosmology · Physics 2019-07-12 Askar B. Abdikamalov , Ahmadjon A. Abdujabbarov , Dimitry Ayzenberg , Daniele Malafarina , Cosimo Bambi , Bobomurat Ahmedov

Recent advances, including gravitational wave detections and imaging of black hole shadows, have strongly validated general relativity. Nevertheless, ongoing cosmological observations suggest potential limitations of general relativity,…

General Relativity and Quantum Cosmology · Physics 2025-08-11 Ali Övgün , Mohsen Fathi

We study the local shadow of the Schwarzschild black hole with a quadrupole distortion and the influence of the external gravitational field on the photon dynamics. The external matter sources modify the light ring structure and lead to the…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Jai Grover , Jutta Kunz , Petya Nedkova , Alexander Wittig , Stoytcho Yazadjiev

Emergent modified gravity presents a new class of gravitational theories in which the structure of space-time with Riemannian geometry of a certain signature is not presupposed. Relying on crucial features of a canonical formulation, the…

General Relativity and Quantum Cosmology · Physics 2024-04-09 Martin Bojowald , Erick I. Duque , Dennis Hartmann

In this paper, we investigate periodic bound orbits and gravitational wave (GW) emission in the Schwarzschild-Bertotti-Robinson (Schwarzschild-BR) spacetime-an exact electrovacuum solution describing a static black hole (BH) immersed in a…

General Relativity and Quantum Cosmology · Physics 2026-02-11 Tursunali Xamidov , Sanjar Shaymatov , Qiang Wu , Tao Zhu