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The M87* black hole shadow observation by the Event Horizon Telescope (EHT) has enabled us to test the modified gravity theories in the extreme-field regime and estimating the black hole parameters. Having this assertion, we investigate the…

General Relativity and Quantum Cosmology · Physics 2023-02-06 Sushant G. Ghosh , Rahul Kumar Walia

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 study shadow aspects of superentropic black holes in four dimensions. Using Hamilton-Jacobi formalism, we first get the null geodesic equations. In the celestial coordinate framework relying on fixed positions of observers, we…

High Energy Physics - Theory · Physics 2022-07-27 A. Belhaj , H. Belmahi , M. Benali

This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Strict conformal symmetry (local Weyl scaling…

General Physics · Physics 2015-06-11 Robert K. Nesbet

In this work, we develop a generalized perturbative framework for gravitational shadows in static, spherically symmetric spacetimes. Building upon the recent two-parameter perturbative framework of Kobialko et al. \cite{Kobialko:2024zhc},…

High Energy Physics - Theory · Physics 2025-12-29 Reggie C. Pantig , Ali Övgün

We consider a spherically symmetric black hole metric in (3+1)-dimensions in presence of a positive cosmological constant $\Lambda$. We use a general approach as proposed in \cite{1} to transform the metric in co-moving coordinates. Then…

General Relativity and Quantum Cosmology · Physics 2022-12-12 Anish Das , Ashis Saha , Sunandan Gangopadhyay

Motivated by recent Event Horizon Telescope findings, we investigate constrained optics of rotating black holes in Einstein-Maxwell-scalar gravity theory. Precisely, we mainly study the parameter effects on two relevant optical concepts…

High Energy Physics - Theory · Physics 2024-11-19 Hajar Belmahi

A distinct visual signature occurs in black holes that are surrounded by optically thin and geometrically thick emission regions. This signature is a sharp-edged dip in brightness that is coincident with the black-hole shadow, which is the…

High Energy Astrophysical Phenomena · Physics 2021-11-03 Thomas Bronzwaer , Heino Falcke

We investigate the shadow behaviors of the superentropic black holes in arbitrary dimensions. Using the Hamilton-Jacobi mechanism, we first obtain the associated null geodesic equations of motion. By help of a spheric stereographic…

High Energy Physics - Theory · Physics 2022-08-10 A. Belhaj , M. Benali , Y. Hassouni

We analyze gravitational lensing and their cast images from thin-disks in shadow observations of a family of spherically symmetric black hole solutions previously derived within the framework of Loop Quantum Gravity. Such black holes depend…

General Relativity and Quantum Cosmology · Physics 2024-09-10 David J. Patiño Pomares , Diego Rubiera-Garcia

We study the shadow produced by a spinning Kaluza-Klein black hole in Einstein gravity coupled to a Maxwell field and a dilaton. The size and the shape of the shadow depend on the mass, the charge, and the angular momentum. We find that,…

General Relativity and Quantum Cosmology · Physics 2013-03-01 Leonardo Amarilla , Ernesto F. Eiroa

The properties of higher-dimensional black holes can differ significantly from those of black holes in four dimensions, since neither the uniqueness theorem, nor the staticity theorem or the topological censorship theorem generalize to…

High Energy Physics - Theory · Physics 2008-11-26 Burkhard Kleihaus , Jutta Kunz , Francisco Navarro-Lerida

For a stationary and axisymmetric black hole, there is a natural way to split the fields into a probe sector and a background sector. The equations of motion for the probe sector enjoy a significantly enhanced symmetry on the black hole…

High Energy Physics - Theory · Physics 2014-04-23 Jianwei Mei

The recent discovery of the novel four-dimensional static and spherically symmetric Gauss-Bonnet black hole provides a promising bed to test Gauss-Bonnet gravity by using astronomical observations [Phys. Rev. Lett. 124, 081301 (2020)]. In…

General Relativity and Quantum Cosmology · Physics 2024-02-22 Shao-Wen Wei , Yu-Xiao Liu

Shape dynamics is classical theory of gravity which agrees with general relativity in many important cases, but possesses different gauge symmetries and constraints. Rather than spacetime diffeomorphism invariance, shape dynamics takes…

General Relativity and Quantum Cosmology · Physics 2016-09-23 Gabriel Herczeg , Vasudev Shyam

Weyl conformal gravity was originally proposed in the early twentieth century as an attempt to unify gravitation and electromagnetism. Since 1989, renewed interest in this fourth-order theory of gravity has emerged following the discovery…

General Relativity and Quantum Cosmology · Physics 2026-04-17 Cristina Blaga , Paul A. Blaga

We consider numerical black hole solutions in the Weyl conformal geometry, and its associated conformally invariant Weyl quadratic gravity. In this model Einstein gravity (with a positive cosmological constant) is recovered in the…

General Relativity and Quantum Cosmology · Physics 2024-11-18 Jin-Zhao Yang , Shahab Shahidi , Tiberiu Harko

Black hole (BH) solution in the conformal Weyl gravity is a generalization of the Schwarzschild spacetime which includes two additional constants appearing when integrating the third order differential equations for gravitational field. One…

General Relativity and Quantum Cosmology · Physics 2021-02-24 R. A. Konoplya

In this paper, we explore two $f(R,T)$ gravity models and derive black hole solutions within these models. We focus on investigating how the $f(R,T)$ model influences the thermodynamic characteristics of black holes by studying their…

General Relativity and Quantum Cosmology · Physics 2025-02-17 Bidyut Hazarika , Prabwal Phukon

We study the shadows of disformal black holes in vector-tensor Galileons modified gravity. Our analysis shows that the apparent image of the black hole in the observer's sky is non-spherical and cuspy, which is in contrast to the Kerr and…

General Relativity and Quantum Cosmology · Physics 2018-01-25 Tsvetan Vetsov , Galin Gyulchev , Stoytcho Yazadjiev