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In this study, we investigate the black hole shadow of an exact black hole solution of the loop quantum gravity (LQG) theory. We discuss some of its optical characteristics after generalizing it to the rotational case, including null…

General Relativity and Quantum Cosmology · Physics 2025-10-21 Shu Luo , Cheng-Hao Li

The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown…

General Relativity and Quantum Cosmology · Physics 2016-06-15 Y. Brihaye , L. Ducobu

Regular black hole is one of the bottom-up solutions designed to eliminate the singularity at the center of black holes. Its horizonless solution has gained interest recently to model ultracompact star. Despite interesting, this proposal is…

General Relativity and Quantum Cosmology · Physics 2024-11-26 M. F. Fauzi , H. S. Ramadhan , A. Sulaksono

In theories where the Lorentz symmetry of gravity is spontaneously broken, a non-minimally coupled bumblebee vector field acquires a nonzero vacuum expectation value, leading to modifications of standard General Relativity (GR). In this…

General Relativity and Quantum Cosmology · Physics 2026-03-11 Faizuddin Ahmed , Shubham Kala , Ahmad Al-Badawi

We study the quintessential properties of the Black Hole solutions in a scalar--tensor theory of gravity with Higgs potential in view of the static and spherically symmetric line element. In view of our earlier results,…

General Relativity and Quantum Cosmology · Physics 2010-11-29 Hemwati Nandan , Nils M. Bezares-Roder , Heinz Dehnen

The nature of black holes (BHs) and their potential deviations from classical General Relativity (GR) remain central questions in modern astrophysics. Nonlinear electrodynamics (NED) offers a promising mechanism to construct regular BHs…

General Relativity and Quantum Cosmology · Physics 2025-12-19 Javokhir Sharipov , Mirzabek Alloqulov , Pankaj Sheoran , Sanjar Shaymatov

Using the Ernst formalism, a novel solution of vacuum general relativity (GR) was recently obtained [1], describing a Schwarzschild black hole (BH) immersed in a nonasymptotically flat rotating background, dubbed swirling universe, with the…

General Relativity and Quantum Cosmology · Physics 2025-07-30 Zeus S. Moreira , Carlos A. R. Herdeiro , Luís C. B. Crispino

We propose a two-parameter, static and spherically symmetric regular geometry, which, for specific parameter values represents a regular black hole. The matter required to support such spacetimes within the framework of General Relativity…

General Relativity and Quantum Cosmology · Physics 2024-05-02 Anjan Kar , Sayan Kar

In this Letter, we have developed a numerically efficient framework for evaluating parameters in metric theories of gravity, and applied it to constrain the horizon-scale magnetic field in the Kerr-Bertotti-Robinson (Kerr-BR) spacetime…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Wentao Liu , Yang Liu , Di Wu , Yu-Xiao Liu

The Chern-Simons modification to general relativity in four dimensions consists of adding to the Einstein-Hilbert term a scalar field that couples to the first class Pontryagin density. In this theory, which has attracted considerable…

General Relativity and Quantum Cosmology · Physics 2010-06-29 Leonardo Amarilla , Ernesto F. Eiroa , Gaston Giribet

General Relativity predicts that the emission close to a black hole must be lensed by its strong gravitational field, illuminating the last photon orbit. This results in a dark circular area known as the black hole 'shadow'. The Event…

Instrumentation and Methods for Astrophysics · Physics 2016-09-02 Leonid Benkevitch , Kazunori Akiyama , Rusen Lu , Shepherd Doeleman , Vincent Fish

Due to the gravitational lensing effect, a black hole casts a shadow larger than its horizon over a bright background, and the shape and size can be calculated. The Event Horizon Telescope collaboration has produced the first direct image…

General Relativity and Quantum Cosmology · Physics 2021-09-28 Rahul Kumar , Balendra Pratap Singh , Md Sabir Ali , Sushant G. Ghosh

We study the equivalence principle, regarded as the cornerstone of general relativity, by analyzing the deformation observable of black hole shadows. Such deformation can arise from new physics and may be expressed as a phenomenological…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-22 Chunlong Li , Sheng-Feng Yan , Lingqin Xue , Xin Ren , Yi-Fu Cai , Damien A. Easson , Ye-Fei Yuan , Hongsheng Zhao

Motivated by the recent work about the Extended Uncertainty Principle (EUP) black holes \cite{Mureika:2018gxl}, we present in this study its extension called the Generalized Extended Uncertainty Principle (GEUP) black holes. In particular,…

General Relativity and Quantum Cosmology · Physics 2023-12-08 Nikko John Leo S. Lobos , Reggie C. Pantig

Black holes are one of the most fascinating predictions of general relativity. They are the natural product of the complete gravitational collapse of matter and today we have a body of observational evidence supporting the existence of…

General Relativity and Quantum Cosmology · Physics 2023-07-26 Cosimo Bambi

In this paper, we analytically present an exact confining charged black hole solution to the scalar-tensor description of regularized 4-dimensional Einstein-Gauss-Bonnet gravity (4DEGBG) coupled to non-linear gauge theory containing…

General Relativity and Quantum Cosmology · Physics 2022-04-28 A. Övgün

Recent observations of black hole shadows have revolutionized our ability to probe gravity in extreme environments. This manuscript presents a novel analytic method to calculate, in leading-order terms, the key parameters of photon sphere…

General Relativity and Quantum Cosmology · Physics 2024-06-04 Vitalii Vertogradov , Ali Övgün

Bumblebee gravity is one of the simplest gravity theories with spontaneous Lorentz symmetry breaking. Since we know a rotating black hole solution in bumblebee gravity, we can potentially test this model with the available astrophysical…

General Relativity and Quantum Cosmology · Physics 2022-08-16 Jiale Gu , Shafqat Riaz , Askar B. Abdikamalov , Dimitry Ayzenberg , Cosimo Bambi

In this paper, we report on exact charged black hole solutions in symmergent gravity with Maxwell field. Symmergent gravity induces the gravitational constant $G$, quadratic curvature coefficient $c_{\rm O}$, and the vacuum energy $V_{\rm…

General Relativity and Quantum Cosmology · Physics 2023-09-12 Beyhan Puliçe , Reggie C. Pantig , Ali Övgün , Durmuş Demir

Black hole solutions in general relativity come with pathologies such as singularity and mass inflation instability, which are believed to be cured by a yet-to-be-found quantum theory of gravity. Without such consistent description, one may…

General Relativity and Quantum Cosmology · Physics 2023-02-14 Rajes Ghosh , Mostafizur Rahman , Akash K Mishra
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