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Related papers: Testing Horndeski Gravity from EHT Observational R…

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The Event Horizon Telescope (EHT) image of M87* provides a direct test of strong-field gravity, measuring an angular shadow diameter $\theta_{d}=42\pm 3~\mu\mathrm{as}$ and a circularity deviation $\Delta C\leq 0.1$. Such observations allow…

General Relativity and Quantum Cosmology · Physics 2026-05-13 Kourosh Nozari , Milad Hajebrahimi , Sara Saghafi , G. Mustafa , Emmanuel N. Saridakis

The Event Horizon Telescope, a global submillimeter wavelength very long baseline interferometry array, produced the first image of supermassive black hole M87* showing a ring of diameter $\theta_d= 42\pm 3\,\mu$as, inferred a black hole…

General Relativity and Quantum Cosmology · Physics 2020-06-18 Rahul Kumar , Amit Kumar , Sushant G. Ghosh

The Event Horizon Telescope (EHT), a global submillimeter wavelength very long baseline interferometry array, unveiled event-horizon-scale images of the supermassive black hole M87* as an asymmetric bright emission ring with a diameter of $…

General Relativity and Quantum Cosmology · Physics 2020-05-12 Rahul Kumar , Sushant G. Ghosh

The Event Horizon Telescope (EHT) collaboration has recently released the first image of a black hole (BH), opening a new window onto tests of general relativity in the strong field regime. In this paper, we derive constraints on the nature…

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

The Event Horizon Telescope (EHT) recently released an image of the supermassive black hole Sgr A* showing an angular shadow diameter $d_{sh}= 48.7 \pm 7\,\mu$as and Schwarzschild shadow deviation $\delta =…

General Relativity and Quantum Cosmology · Physics 2023-02-28 Sushant G. Ghosh , Misba Afrin

Thanks to the release of the extraordinary EHT image of shadow attributed to the M87* supermassive black hole (SMBH), we have a novel window to assess the validity of fundamental physics in the strong-field regime. Motivated by this, we…

General Relativity and Quantum Cosmology · Physics 2021-09-22 Mohsen Khodadi , Gaetano Lambiase , David F. Mota

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

We study gravitational lensing in strong-field limit by a static spherically symmetric black hole in quartic scalar field Horndeski gravity having additional hair parameter $q$, evading the no-hair theorem. We find an increase in the…

General Relativity and Quantum Cosmology · Physics 2022-06-01 Jitendra Kumar , Shafqat Ul Islam , Sushant G. Ghosh

The Event Horizon Telescope (EHT) has guided strong-field gravitational physics by providing the first direct images of the supermassive black holes M87* and Sagittarius A*. The EHT observations offer unprecedented opportunities to test…

General Relativity and Quantum Cosmology · Physics 2026-04-16 Towheed Ahmad Nengroo , Shafqat Ul Islam , Sushant G. Ghosh

Inspired by the observations of supermassive black hole M87* in \emph{Event Horizon Telescope }(EHT) experiment, a remarkable surge in black hole physics is to use the black hole shadow's observables to distinguish general relativity (GR)…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Yuan Meng , Xiao-Mei Kuang , Zi-Yu Tang

In this study, we have considered the Kerr-like black hole (BH) model in Horndeski gravity and analyse the visual characteristics of shadow images under two illumination models, such as a celestial light source and a thin accretion disk. To…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Xiao-Xiong Zeng , Chen-Yu Yang , M. Israr Aslam , Rabia Saleem

Recent times witnessed a surge of interest in strong gravitational lensing by black holes due to the Event Horizon Telescope (EHT) results, which suggest comparing the black hole lensing in general relativity and modified gravity theories.…

General Relativity and Quantum Cosmology · Physics 2021-06-30 Shafqat Ul Islam , Sushant G. Ghosh

The lack of rotating black holes, typically found in nature, hinders testing modified gravity from astrophysical observations. We present the axially symmetric counterpart of an existing spherical hairy black hole in Horndeski gravity…

General Relativity and Quantum Cosmology · Physics 2022-06-27 Rahul Kumar Walia , Sunil D. Maharaj , Sushant G. Ghosh

A mathematically consistent rotating black hole model in loop quantum gravity (LQG) is yet lacking. The scarcity of rotating black hole solutions in LQG substantially hampers the development of testing LQG from observations, e.g., from the…

General Relativity and Quantum Cosmology · Physics 2023-01-25 Shafqat Ul Islam , Jitendra Kumar , Rahul Kumar Walia , Sushant G. Ghosh

The advent of the Event Horizon Telescope (EHT), a millimeter-wave very-long baseline interferometric array, has enabled spatially-resolved studies of the sub-horizon-scale structure for a handful of supermassive black holes. Among these,…

High Energy Astrophysical Phenomena · Physics 2014-03-05 Avery E. Broderick , Tim Johannsen , Abraham Loeb , Dimitrios Psaltis

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

Searching for violations of the no-hair theorem (NHT) is a powerful way to test gravity, and more generally fundamental physics, particularly with regards to the existence of additional scalar fields. The first observation of a black hole…

General Relativity and Quantum Cosmology · Physics 2020-09-15 Mohsen Khodadi , Alireza Allahyari , Sunny Vagnozzi , David F. Mota

We investigate Einstein-\AE ther gravity in light of the recent Event Horizon Telescope (EHT) observations of the M87*. The shape and size of the observed black hole shadow contains information of the geometry in its vicinity, and thus one…

General Relativity and Quantum Cosmology · Physics 2021-05-20 Mohsen Khodadi , Emmanuel N. Saridakis

The M87* black hole shadow observation by the Event Horizon Telescope (EHT) has enabled us to test the modified gravity theories in the extreme-field regime and estimating the black hole parameters. Having this assertion, we investigate the…

General Relativity and Quantum Cosmology · Physics 2023-02-06 Sushant G. Ghosh , Rahul Kumar Walia

The Event Horizon Telescope (EHT) collaboration unveiled event-horizon-scale images of the supermassive black holes (SMBHs) M87* and Sgr A*, revealing a dark brightness depression, namely the black hole shadow, whose shape and size may…

General Relativity and Quantum Cosmology · Physics 2023-07-27 Misba Afrin , Sushant G. Ghosh
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