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By considering the celestial light source and the thin disk source, we employ the backward ray-tracing method to carefully study the shadow, inner shadow and observational images of the non-singular rotating black holes in loop quantum…

General Relativity and Quantum Cosmology · Physics 2024-10-30 Guo-Ping Li , He-Bin Zheng , Ke-Jian He , Qing-Quan Jiang

Cosmic expansion is expected to influence on the size of black hole shadow observed by comoving observer. Except the simplest case of Schwarzschild black hole in de Sitter universe, analytical approach for calculation of shadow size in…

General Relativity and Quantum Cosmology · Physics 2018-10-24 Gennady S. Bisnovatyi-Kogan , Oleg Yu. Tsupko

We show that, away from the axis of symmetry, no continuous degeneration exists between the shadows of observers at any point in the exterior region of any Kerr-Newman black hole spacetime of unit mass. Therefore, except possibly for…

General Relativity and Quantum Cosmology · Physics 2024-10-29 Marc Mars , Claudio F. Paganini , Marius A. Oancea

We consider a simple model of a black hole surrounded by a toroidal structure and experiencing deformation due to magnetic field and the tidal force. For this system we construct the shadows of Preston-Poisson black hole, apply it to…

General Relativity and Quantum Cosmology · Physics 2020-08-14 R. A. Konoplya , Jan Schee , Dmitriy Ovchinnikov

The scarcity of quantum gravity (QG) inspired rotating black holes limits the progress of testing QG through Event Horizon Telescope (EHT) observations. The EHT imaged the supermassive black holes, Sgr A* and M87*, revealing an angular…

General Relativity and Quantum Cosmology · Physics 2025-04-30 Heena Ali , Shafqat Ul Islam , Sushant G. Ghosh

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.…

The groundbreaking image of the black hole at the center of the M87 galaxy has raised questions at the intersection of observational astronomy and black hole physics. How well can the radius of a black hole shadow can be measured, and can…

General Relativity and Quantum Cosmology · Physics 2022-02-02 Adam Bauer , Alejandro Cárdenas-Avendaño , Charles F. Gammie , Nicolás Yunes

The recent Event Horizon Telescope (EHT) observations of the M87* have led to a surge of interest in studying the shadow of black holes. Besides, investigation of time evolution and lifetime of black holes helps us to veto/restrict some…

General Relativity and Quantum Cosmology · Physics 2023-02-14 S. H. Hendi , Kh. Jafarzade , B. Eslam Panah

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

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

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

The shadow of a black hole can be one of the strong observational evidences for stationary black holes. If we see shadows at the center of galaxies, we would say whether the observed compact objects are black holes. In this paper, we…

General Relativity and Quantum Cosmology · Physics 2018-03-20 Naoki Tsukamoto

The EHT observation revealed event horizon-scale images of the supermassive black holes Sgr A* and M87* and these results are consistent with the shadow of a Kerr black hole as predicted by general relativity. However, Kerr-like rotating…

General Relativity and Quantum Cosmology · Physics 2024-10-10 Shafqat Ul Islam , Sushant G. Ghosh , Sunil D. Maharaj

The recent detection of gravitational waves from black hole coalescences and the first image of the black hole shadow enhance the possibilities of testing gravitational theories in the strong-field regime. In this paper, we study the…

General Relativity and Quantum Cosmology · Physics 2020-05-27 Che-Yu Chen

In general relativity, isolated black holes are invisible due to an infinitely large redshift of photons propagating from the event horizon to the remote observer. However, the dark shadow (silhouette) of a black hole can be visible on the…

General Relativity and Quantum Cosmology · Physics 2020-08-31 Vyacheslav I. Dokuchaev , Natalia O. Nazarova

The spacetime singularities in classical general relativity predicted by the celebrated singularity theorems are formed at the end of gravitational collapse. Quantum gravity is the expected theory to resolve the singularity problem, but we…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Sushant G. Ghosh , Muhammed Amir , Sunil D. Maharaj

The shadows cast by non-rotating and rotating modified gravity (MOG) black holes are determined by the two parameters mass $M$ and angular momentum $J=Ma$. The sizes of the shadows cast by the spherically symmetric static Schwarzschild-MOG…

General Relativity and Quantum Cosmology · Physics 2015-03-26 J. W. Moffat

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

In light of the Event Horizon Telescope (EHT) images of the supermassive black holes $\textrm{Sgr A}^\star$ and $\textrm{M87}^\star$, we explore a potential supersymmetry suspicion within the observational data. Specifically, we investigate…

High Energy Physics - Theory · Physics 2024-09-05 L. Chakhchi , H. El Moumni , K. Masmar

We consider rational nonlinear electrodynamics with the Lagrangian ${\cal L} = -{\cal F}/(1+2\beta{\cal F})$ (${\cal F}=(1/4)F_{\mu\nu}F^{\mu\nu}$ is the Lorentz-invariant), proposed in [63], coupled to General Relativity. The effective…

General Relativity and Quantum Cosmology · Physics 2020-12-02 S. I. Kruglov