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The Event Horizon Telescope (EHT) recently released the first linearly polarized images of the accretion flow around the supermassive black hole Messier 87*, hereafter \m{}. The spiraling polarization pattern found in EHT images favored…

High Energy Astrophysical Phenomena · Physics 2022-04-20 Daniel C. M. Palumbo , George N. Wong

Two critical aspects of radio interferometric imaging analysis are data calibration and deconvolution of the point spread function (PSF) structure. Both of these are particularly important for high-frequency observations using a VLBI…

Instrumentation and Methods for Astrophysics · Physics 2024-09-27 Makoto Miyoshi , Yoshiaki Kato , Junichiro Makino

In this work, we study how to infer the orbit of a supermassive black hole binary (SMBHB) by time-dependent measurements with Very Long Baseline Interferometry (VLBI), such as the Event Horizon Telescope (EHT). Assuming a point-like…

General Relativity and Quantum Cosmology · Physics 2022-03-14 Yun Fang , Huan Yang

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

We consider a time-like geodesics in the background of rotating Einstein-Born-Infeld (EBI) black hole to examine the horizon and ergosphere structure. The effective potential that governs the particle's motion in the spacetime and the…

General Relativity and Quantum Cosmology · Physics 2021-08-11 Gulmina Zaman Babar , Farruh Atamurotov , Shafqat Ul Islam , Sushant G. Ghosh

Testing gravity theory in the strong field region becomes a reality due to the observations of gravitational waves and black hole shadows. In this paper, we discuss how to constrain the possible deviations of the classical general…

General Relativity and Quantum Cosmology · Physics 2019-09-10 S. X. Tian , Zong-Hong Zhu

The Event Horizon Telescope (EHT) collaboration has produced the first resolved images of the supermassive black holes at the centre of our galaxy and at the centre of the elliptical galaxy M87. As both technology and analysis pipelines…

High Energy Astrophysical Phenomena · Physics 2023-01-04 Angelo Ricarte , Charles Gammie , Ramesh Narayan , Ben S. Prather

The observable quantities that carry the most information regarding the structures of the images of black holes in the interferometric observations with the Event Horizon Telescope are the closure phases along different baseline triangles.…

High Energy Astrophysical Phenomena · Physics 2017-07-26 Lia Medeiros , Chi-kwan Chan , Feryal Özel , Dimitrios Psaltis , Junhan Kim , Daniel Marrone , Aleksander Sądowski

Spin measurement of the 6.5 billion solar mass black hole in M87 from the Event Horizon Telescope image is the latest in a series that span a wide range in values, but that tend to share the feature of co-rotation between the accretion flow…

High Energy Astrophysical Phenomena · Physics 2020-05-20 David Garofalo

Light passing near a black hole can follow multiple paths from an emission source to an observer due to strong gravitational lensing. Photons following different paths take different amounts of time to reach the observer, which produces an…

High Energy Astrophysical Phenomena · Physics 2024-11-25 George N. Wong , Lia Medeiros , Alejandro Cárdenas-Avendaño , James M Stone

Following up on a recent analysis by Psaltis et al. [Phys. Rev. Lett. 125, 141104 (2020)], we show that the observed shadow size of M87$^*$ can be used to unambiguously and robustly constrain the black hole geometry in the vicinity of the…

General Relativity and Quantum Cosmology · Physics 2021-10-13 Sebastian H. Völkel , Enrico Barausse , Nicola Franchini , Avery E. Broderick

The horizon-scale images of black holes obtained with the Event Horizon Telescope have provided new probes of their metrics and tests of General Relativity. The images are characterized by a bright, near circular ring from the…

High Energy Astrophysical Phenomena · Physics 2022-12-28 Feryal Ozel , Dimitrios Psaltis , Ziri Younsi

The Event Horizon Telescope (EHT) has revealed the horizon-scale radiation of Sagittarius A* (Sgr A*), our galaxy's central supermassive black hole, offering a new platform to test gravitational theories. The next step involves studying…

High Energy Astrophysical Phenomena · Physics 2025-01-16 Kotaro Moriyama , Alejandro Cruz-Osorio , Yosuke Mizuno , Indu K. Dihingia , Akhil Uniyal

We investigate constraints on the distribution of dark matter in the neighbourhood of the Galactic centre that may eventually be attained with the high-resolution Event Horizon Telescope (EHT). The shadow of a black hole in vacuum is used…

Astrophysics of Galaxies · Physics 2013-08-15 Thomas Lacroix , Joseph Silk

We explore the entropic uncertainty relation in the curved background outside a Schwarzschild black hole, and find that Hawking radiation introduces a nontrivial modification on the uncertainty bound for particular observer, therefore it…

High Energy Physics - Theory · Physics 2015-03-10 Jun Feng , Yao-Zhong Zhang , Mark D. Gould , Heng Fan

The low-energy effective action of String Theory introduces corrections to the dilaton-graviton sector, resulting in deformed black holes beyond general relativity. We analyze extreme mass-ratio inspiral systems (EMRIs), where a…

General Relativity and Quantum Cosmology · Physics 2024-08-29 Chao Zhang , Guoyang Fu , Yungui Gong

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

Inspired by the two different dark matter frameworks that were studied recently: one that arises from the non-local effects of entanglement entropy as emergent gravity (characterized by the parameter $\xi(M)$, and zero-point scale length…

General Relativity and Quantum Cosmology · Physics 2024-06-11 Reggie C. Pantig

Swift J164449.3+573451 is an exciting transient event, likely powered by the tidal disruption of a star by a massive black hole. The distance to the source, its transient nature, and high internal column density serve to complicate several…

High Energy Astrophysical Phenomena · Physics 2015-05-28 J. M. Miller , K. Gultekin

There are now multiple direct probes of the region near black hole horizons, including direct imaging with the Event Horizon Telescope (EHT). As a result, it is now of considerable interest to identify what aspects of the underlying…

General Relativity and Quantum Cosmology · Physics 2023-11-06 Kiana Salehi , Avery Broderick , Boris Georgiev