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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

We develop a fully numerical framework to compute and visualize the \emph{hypershadow}\cite{Novo:2024wyn}, the three-dimensional generalization of the black hole shadow in five-dimensional spacetimes. Our method is based on backward ray…

General Relativity and Quantum Cosmology · Physics 2026-03-06 Jianzhi Yang

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

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A$^*$), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric…

High Energy Astrophysical Phenomena · Physics 2023-11-17 The Event Horizon Telescope Collaboration

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 recently released images of the supermassive black holes in the M87 galaxy and the galaxy of our own make probing black hole spacetimes and testing general relativity (GR) possible. The violation of equatorial reflection symmetry of…

General Relativity and Quantum Cosmology · Physics 2022-08-04 Che-Yu Chen

The Event Horizon Telescope (EHT) collaboration's image of the compact object at the galactic center is the first direct evidence of the supermassive black hole (BH) Sgr A$^*$. The shadow of Sgr A$^*$ has an angular diameter $d_{sh}= 48.7…

General Relativity and Quantum Cosmology · Physics 2023-02-24 Misba Afrin , Sunny Vagnozzi , Sushant G. Ghosh

The Event Horizon Telescope (EHT), a global 230 GHz VLBI array, achieves an angular resolution of ${\approx} 20\,\mu{\rm as}$, sufficient to resolve the supermassive black hole Sagittarius A* (Sgr A*). This resolution may soon enable…

Instrumentation and Methods for Astrophysics · Physics 2019-01-09 Ziyan Zhu , Michael D. Johnson , Ramesh Narayan

For an observer, the Black Hole (BH) shadow is the BH's apparent image in the sky due to the gravitational lensing of nearby radiation, emitted by an external source. A recent class of solutions dubbed Kerr BHs with scalar hair possess…

General Relativity and Quantum Cosmology · Physics 2016-08-17 Pedro V. P. Cunha , Carlos A. R. Herdeiro , Eugen Radu , Helgi F. Runarsson

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

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

Upcoming VLBI observations will resolve nearby supermassive black holes, most notably Sagittarius A* and M87, on event horizon-scales. Recent observations of Sagittarius A* with the Event Horizon Telescope have revealed horizon-scale…

High Energy Astrophysical Phenomena · Physics 2020-04-15 Ziri Younsi , Oliver Porth , Yosuke Mizuno , Christian M. Fromm , Hector Olivares

Four spherically symmetric but non-asymptotically flat black hole solutions surrounded with spherical dark matter distribution perceived under the minimal length scale effect is derived via the generalized uncertainty principle. Here, the…

General Relativity and Quantum Cosmology · Physics 2023-12-08 Ali Övgün , Lemuel John F. Sese , Reggie C. Pantig

The half opening angle of a Kerr black-hole shadow is always equal to (5+-0.2)GM/Dc^2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within…

High Energy Astrophysical Phenomena · Physics 2015-12-02 Dimitrios Psaltis , Feryal Ozel , Chi-Kwan Chan , Daniel P. Marrone

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

We consider a black hole mimicker given by an exact solution of the stationary and axially symmetric field equations in vacuum known as the $\delta$-Kerr metric. We study its optical properties based on a ray-tracing code for photon motion…

General Relativity and Quantum Cosmology · Physics 2022-07-25 Song Li , Temurbek Mirzaev , Ahmadjon A. Abdujabbarov , Daniele Malafarina , Bobomurat Ahmedov , Wen-Biao Han

The Event Horizon Telescope (EHT) observation unveiled the first image of supermassive black hole Sgr A* showing a shadow of diameter $\theta_{sh}= 48.7 \pm 7\,\mu$as with fractional deviation from the Schwarzschild black hole shadow…

General Relativity and Quantum Cosmology · Physics 2022-11-10 Rahul Kumar Walia , Sushant G Ghosh , Sunil D Maharaj

The Event Horizon Telescope is a global very-long baseline interferometer capable of probing potential deviations from the Kerr metric, which is believed to provide the unique description of astrophysical black holes. Here we report an…

High Energy Astrophysical Phenomena · Physics 2016-09-02 Tim Johannsen , Carlos Wang , Avery E. Broderick , Sheperd S. Doeleman , Vincent L. Fish , Abraham Loeb , Dimitrios Psaltis

When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the…

Astrophysics of Galaxies · Physics 2019-07-08 The Event Horizon Telescope Collaboration

The unprecedented image of the M87* supermassive black hole has sparked some controversy over its usefulness as a test of the general relativistic Kerr metric. The criticism is mainly related to the black hole's quasi-circular shadow and…

General Relativity and Quantum Cosmology · Physics 2021-10-22 Kostas Glampedakis , George Pappas