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Imaging of the shadow around supermassive black hole (SMBH) horizon with a very long baseline interferometry (VLBI) is recognized recently as a powerful tool for experimental testing of Einstein's General relativity. The Event Horizon…

Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical…

The Event Horizon Telescope Collaboration (EHTC) has presented first - dynamic-range limited - images of the black hole shadows in M87 and Sgr A*. The next generation Event Horizon Telescope (ngEHT) will provide higher sensitivity and…

High Energy Astrophysical Phenomena · Physics 2023-03-14 Bidisha Bandyopadhyay , Christian Fendt , Dominik R. G. Schleicher , Javier Lagunas , Javier Pedreros , Neil M. Nagar , Felipe Agurto

The Event Horizon Telescope (EHT) imaging of the supermassive black holes at the centers of Messier 87 galaxy and the Milky Way galaxy marks a significant step in observing the photon rings and central brightness depression that define the…

High Energy Astrophysical Phenomena · Physics 2024-11-14 Soroush Zare , Luis M. Nieto , Xing-Hui Feng , Shi-Hai Dong , Hassan Hassanabadi

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 Event Horizon Telescope (EHT) has recently observed the image and shadow of the supermassive compact object Sagittarius A$^*$ (Sgr A$^*$). According to the EHT collaboration, the observed image is consistent with the expected appearance…

General Relativity and Quantum Cosmology · Physics 2023-05-29 Rajibul Shaikh

Motivated by (i) more and more interest in strong gravitational lensing by supermassive black holes due to the achievement of EHT observations, (ii) the ongoing popular topic on the possibility of Lorentz symmetry being broken in…

General Relativity and Quantum Cosmology · Physics 2022-11-01 Xiao-Mei Kuang , Ali Övgün

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

Recently, the \textit{EHT} collaboration unveiled the shadow images of the supermassive black hole (SMBH) M87* and Sgr A*, with angular radii of $42\pm3$\,$\mu$as and $48.7\pm7.0$\,$\mu$as, respectively. These observations are consistent…

High Energy Astrophysical Phenomena · Physics 2025-10-07 Yuan Tan , Youjun Lu , Kunyu Song

Ongoing millimeter VLBI observations with the Event Horizon Telescope allow unprecedented study of the innermost portion of black hole accretion flows. Interpreting the observations requires relativistic, time-dependent physical modeling.…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Jason Dexter , Eric Agol , P. Chris Fragile , Jonathan C. McKinney

The Event Horizon Telescope (EHT) images of the supermassive black hole at the center of the galaxy M 87 provided the first image of the accretion environment on horizon scales. General relativity predicts that the image of the shadow…

High Energy Astrophysical Phenomena · Physics 2022-12-14 Paul Tiede , Avery E. Broderick , Daniel C. M. Palumbo , Andrew Chael

This article deals with the study of some properties of the static and rotating black holes in Kalb-Ramond gravity in four dimensional spacetime. First, we discuss the action of the corresponding theory and the static black hole metric.…

General Relativity and Quantum Cosmology · Physics 2023-10-20 M. Zubair , Muhammad Ali Raza , Eiman Maqsood

The recently obtained hairy Kerr black holes, due to additional sources or surrounding fluid, like dark matter, with conserved energy-momentum tensor, have a deviation $\alpha$ and primary hair $l_0$, apart from rotation parameter $a$ and…

General Relativity and Quantum Cosmology · Physics 2021-06-01 Misba Afrin , Rahul Kumar , Sushant G. Ghosh

The recent observation of the shadow of the supermassive compact object M87$^*$ by the Event Horizon Telescope (EHT) collaboration has opened up a new window to probe the strong gravity regime. In this paper, we study shadows cast by two…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Rajibul Shaikh , Kunal Pal , Kuntal Pal , Tapobrata Sarkar

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

Observations of the black hole shadow of supermassive black holes, such as Sagittarius A* at the center of our Milky Way galaxy, allow us to study the properties of black holes and the nature of strong-field gravity. According to the Kerr…

General Relativity and Quantum Cosmology · Physics 2018-11-14 Dimitry Ayzenberg , Nicolas Yunes

In this study, we investigate a static, spherically symmetric black hole (BH) within the framework of Loop Quantum Gravity (LQG) surrounded by quintessence field. Our comprehensive analysis shows that the interplay between quantum…

General Relativity and Quantum Cosmology · Physics 2025-05-20 Ahmad Al-Badawi , Faizuddin Ahmed , İzzet Sakallı

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

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 show how Event Horizon Telescope (EHT) observations of the supermassive object at the center of M87 can constrain deviations from General Relativity (GR) in a relatively model-independent way. We focus on the class of theories whose…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Markus Rummel , C. P. Burgess