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Related papers: Einstein-\AE ther Gravity in the light of Event Ho…

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According to the celebrated singularity theorems, space-time singularities in general relativity are inevitable. However, it is generally believed that singularities do not exist in nature, and their existence suggests the necessity of a…

General Relativity and Quantum Cosmology · Physics 2024-11-22 Carlos A. Benavides-Gallego , Swarnim Shashank , Haiguang Xu

The quantum-corrected black hole model demonstrates significant potential in the study of gravitational lensing effects. By incorporating quantum effects, this model addresses the singularity problem in classical black holes. In this paper,…

General Relativity and Quantum Cosmology · Physics 2025-03-12 Lai Zhao , Meirong Tang , Zhaoyi Xu

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…

We analytically investigate the shadows cast by rotating black holes in the asymptotically safe gravity (ASG) by deriving complete null geodesics and observables using the Hamilton-Jacobi equation and Carter separable method. It turns out…

General Relativity and Quantum Cosmology · Physics 2020-07-13 Rahul Kumar , Balendra Pratap Singh , Sushant G. Ghosh

This paper investigates photon motion in black hole of Einstein-Maxwell-dilaton theory, exploring black hole shadows and observational characteristics under various accretion models. We first give the relation of the event horizon, photon…

General Relativity and Quantum Cosmology · Physics 2025-12-16 Junlin Qin , Hong-Er Gong , Yusen Wang , Zhan-Feng Mai , Bofeng Wu , Sen Guo , Enwei Liang

Using a continued fraction ansatz we obtain an analytic approximation for a spherically symmetric black hole solution to Einsteinian Quartic Gravity (EQG), the next simplest Generalized Quasi-Topological Gravity (GQTG) after Einsteinian…

General Relativity and Quantum Cosmology · Physics 2020-09-02 H. Khodabakhshi , A. Giaimo , Robert B. Mann

The Event Horizon Telescope has recently provided the first image of the dark shadow around the supermassive black hole M87*. The observation of a highly circular shadow provides strong limits on deviations of M87*'s quadrupole moment from…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Sunny Vagnozzi , Luca Visinelli

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

Reconstructing images from the Event Horizon Telescope (EHT) observations of M87*, the supermassive black hole at the center of the galaxy M87, depends on a prior to impose desired image statistics. However, given the impossibility of…

Instrumentation and Methods for Astrophysics · Physics 2024-11-12 Berthy T. Feng , Katherine L. Bouman , William T. Freeman

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

Event Horizon Telescope (EHT) observations of M87* provide a means of constraining parameters of both the black hole and its surrounding plasma. However, intrinsic variability of the emitting material introduces a major source of systematic…

High Energy Astrophysical Phenomena · Physics 2025-11-27 Dominic O. Chang , Micael D. Johnson , Paul Tiede

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

We investigate the shadow, deflection angle, and the greybody bounding of a Schwarzschild-AdS/dS black hole in scale-dependent gravity. We used the EHT data to constrain the parameter $\epsilon$. We have found that within the $1\sigma$…

General Relativity and Quantum Cosmology · Physics 2023-03-06 Ali Övgün , Reggie C. Pantig , Ángel Rincón

A Kerr-Sen-like black hole solution appears in the Einstein-bumblebee theory of gravity. The solution contains contains a Lorentz violating parameter in an explicit manner. We study the null geodesics in the background of this Kerr-Sen-like…

General Relativity and Quantum Cosmology · Physics 2022-02-23 Sohan Kumar Jha , Sahazada Aziz , Anisur Rahaman

(abridged) In the first two papers of this publication series, we present a comprehensive library of synthetic EHT observations and used this library to train and validate Bayesian neural networks for the parameter inference of accreting…

High Energy Astrophysical Phenomena · Physics 2025-06-18 M. Janssen , C. -k. Chan , J. Davelaar , M. Wielgus

Gravity models given by higher-order scalar curvature corrections are believed to bear important consequences. The Einstein-Bel-Robinson gravity, with quartic curvature modification, motivated Sajadi et al to explore static spherically…

General Relativity and Quantum Cosmology · Physics 2024-04-11 B. Hamil , B. C. Lütfüoğlu

We set out to bridge the gap between regular black-hole spacetimes and observations of a black-hole shadow by the Event Horizon Telescope. We explore modifications of spinning and non-spinning black-hole spacetimes inspired by…

General Relativity and Quantum Cosmology · Physics 2019-06-19 Aaron Held , Roman Gold , Astrid Eichhorn

In this paper, we study the influence of the parameters for the accelerating Kerr-Newman black hole on the shadows and the constraints, extensively. We find that the rotating parameter $a$, the charge parameter $e$, and the inclination…

General Relativity and Quantum Cosmology · Physics 2023-11-21 Tao-Tao Sui , Qi-Ming Fu , Wen-Di Guo

Motivated by recent Event Horizon Telescope findings, we investigate constrained optics of rotating black holes in Einstein-Maxwell-scalar gravity theory. Precisely, we mainly study the parameter effects on two relevant optical concepts…

High Energy Physics - Theory · Physics 2024-11-19 Hajar Belmahi

We consider static black holes in Einstein gravity and study parameters characterizing the black hole size, namely the radii of the horizon $R_+$, photon sphere $R_{\rm ph}$ and black hole shadow $R_{\rm sh}$. We find a sequence of…

General Relativity and Quantum Cosmology · Physics 2020-03-04 H. Lu , Hong-Da Lyu