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Related papers: Black Hole Shadows Constrain Extended Gravity

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Advancements in the black hole shadow observations may allow us not only to investigate physics in the strong gravity regime, but also to use them in cosmological studies. In this paper, we propose to use the shadow of supermassive black…

General Relativity and Quantum Cosmology · Physics 2020-02-21 Oleg Yu. Tsupko , Zuhui Fan , Gennady S. Bisnovatyi-Kogan

We establish a thermodynamic-optical duality that directly bridges the semiclassical quantum evaporation of black holes with their classical macroscopic geometry. By employing a diffeomorphic inversion, we re-parameterize the intrinsic…

General Relativity and Quantum Cosmology · Physics 2026-04-27 Nikko John Leo S. Lobos , Emmanuel T. Rodulfo

In the paper, only Static Spherically Symmetric space-times in four dimensions are considered within modified gravity models. The non-singular static metrics, including black holes not admitting a de Sitter core in the center and…

General Relativity and Quantum Cosmology · Physics 2024-10-07 A. S. Agrawal , Sergio Zerbini , B. Mishra

The improved version of ghost-free $f(\mathcal{G})$ gravity introduced in Phys.~Lett.~B \textbf{631} (2005), 1-6 is proposed and investigated. It is demonstrated that improved ghost-free $f(\mathcal{G})$ gravity may be consistently applied…

General Relativity and Quantum Cosmology · Physics 2024-10-16 Shin'ichi Nojiri , S. D. Odintsov

In this work, we investigate the shadow properties of the Kerr-Newman-Anti-de Sitter black hole coupled to a nonlinear electrodynamics. We construct the shadow by employing the celestial coordinate approach for observers located at finite…

General Relativity and Quantum Cosmology · Physics 2025-08-20 Mohsen Fathi

In this paper, an analytic generalization of the weak field deflection angle (WDA) is derived by utilizing the current non-asymptotically flat generalization of the Gauss-Bonnet theorem. The derived formula is valid for any…

General Relativity and Quantum Cosmology · Physics 2025-06-23 Reggie C. Pantig

With the help of Newman-Janis method new spinning black hole (BH) solution for a non-local gravity model was obtained. We show how to account the quantum gravitational correction part in BH shadows modelling using spinning BH metrics with a…

General Relativity and Quantum Cosmology · Physics 2024-04-26 Stanislav Alexeyev , Artem Baiderin , Alexandra Nemtinova , Oleg Zenin

The Event Horizon Telescope (EHT), a global very long baseline interferometry array operating at millimetre wavelengths, is spatially resolving the immediate environments of black holes for the first time. The current observations of the…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Ayman Bin Kamruddin , Jason Dexter

A gravitational theory is formulated by considering the physical processes underlying relativistic dilation of time and contraction of space. It is shown that the point mass solution of general relativity's field equation - the…

General Relativity and Quantum Cosmology · Physics 2015-08-25 James W. Douglass

We investigate the strong gravitational lensing and shadow properties of the black hole in the context of bumblebee gravity, characterized by a global monopole charge $\kappa\eta^2$ and a Lorentz symmetry breaking parameter $\gamma$. We…

General Relativity and Quantum Cosmology · Physics 2026-01-01 Bijendra Kumar Vishvakarma , Shubham Kala

The most general action for a scalar field coupled to gravity that leads to second order field equations for both the metric and the scalar --- Horndeski's theory --- is considered, with the extra assumption that the scalar satisfies shift…

General Relativity and Quantum Cosmology · Physics 2014-08-13 Thomas P. Sotiriou , Shuang-Yong Zhou

Consideration of extra spatial dimensions is motivated by the unification of gravity with other interactions, the achievement of the ultimate framework of quantum gravity, and fundamental problems in particle physics and cosmology. Much…

General Relativity and Quantum Cosmology · Physics 2024-09-10 Kourosh Nozari , Sara Saghafi , Ali Mohammadpour

By using the zero-point length effect, we construct a new class of charged black hole solutions in the framework of three dimensional Gauss-Bonnet (GB) gravity with Maxwell electrodynamics. The gravitational and electromagnetic potentials…

General Physics · Physics 2025-11-14 Kimet Jusufi , Mubasher Jamil , Ahmad Sheykhi

We derive a class of regular black holes from the proper-time renormalization group approach to asymptotically safe gravity. A central challenge is the robustness of physical predictions to the regularization scheme. We address this by…

General Relativity and Quantum Cosmology · Physics 2025-12-22 Alfio Bonanno , Roman A. Konoplya , Giovanni Oglialoro , Andrea Spina

We study the shadow cast by rotating black holes surrounded by plasma in the context of the 4D Einstein-Gauss-Bonnet theory of gravity. The metric for these black holes results from applying the Newman-Janis algorithm to a spherically…

General Relativity and Quantum Cosmology · Physics 2023-01-30 Javier Badía , Ernesto F. Eiroa

We have studied the shadows of a circular disformal Kerr black hole with a deformation parameter, which represents a rotating solution within a generalized scalar-tensor framework of Horndeski gravity that characterized by second-order…

General Relativity and Quantum Cosmology · Physics 2026-01-06 Fen Long , Songbai Chen , Jiliang Jing

In a new gravitational theory with the trace anomaly recently proposed by Gabadadze, we study the existence of hairy black hole solutions on a static and spherically symmetric background. In this theory, the effective 4-dimensional action…

General Relativity and Quantum Cosmology · Physics 2023-07-07 Shinji Tsujikawa

We study the gravitational lensing effects of a static, asymptotically flat black hole with primary scalar hair in Beyond Horndeski gravity, focusing on the strong lensing regime. Recently, in Ref. [1], we placed constraints on the scalar…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Mohsen Fathi

Previous works on black hole shadows have been primarily focused on studying shadows in asymptotically flat and anti-de Sitter space times. In the present work, we find general expressions for asymptotically de Sitter black hole shadow as…

General Relativity and Quantum Cosmology · Physics 2020-07-29 Rittick Roy , Sayan Chakrabarti

Quantum effects in general induce scale dependence in the coupling constants. We explore this possibility in gravity, with a scale-dependent Newton coupling. When applied to Kerr black holes with such a running coupling, the consistency of…

General Relativity and Quantum Cosmology · Physics 2026-02-19 Che-Yu Chen , Chiang-Mei Chen , Nobuyoshi Ohta