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The idea of extra spatial dimensions arises from attempts to unify gravity with other fundamental interactions, develop a consistent theory of quantum gravity, and address open problems in particle physics and cosmology. Considerable…

General Relativity and Quantum Cosmology · Physics 2025-11-04 Kourosh Nozari , Sara Saghafi , Zeynab Ramezanpasandi

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

We show that the observed angular diameter of the shadow of the ultra compact object Sgr A*, favours the existence of an extra spatial dimension. This holds irrespective of the nature of the ultra compact object, i.e., whether it is a…

General Relativity and Quantum Cosmology · Physics 2022-12-07 Indrani Banerjee , Sumanta Chakraborty , Soumitra SenGupta

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

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

Motivated by M-theory/superstring inspired models, we investigate certain behaviors of the deflection angle and the shadow geometrical shapes of higher dimensional quintessential black holes associated with two values of the dark energy…

General Relativity and Quantum Cosmology · Physics 2020-10-28 A. Belhaj , M. Benali , A. El Balali , H. El Moumni , S-E. Ennadifi

Recently, the Event Horizon Telescope (EHT) achieved the realization of an image of the supermassive black hole $\textrm{Sgr~A}^\star$ showing an angular shadow diameter $\mathcal{D}= 48.7 \pm 7\mu as$ and the fractional deviation…

General Relativity and Quantum Cosmology · Physics 2024-04-23 L. Chakhchi , H. El Moumni , K. Masmar

The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in…

General Relativity and Quantum Cosmology · Physics 2020-10-05 Dimitrios Psaltis , Lia Medeiros , Pierre Christian , Feryal Ozel , Kazunori Akiyama , Antxon Alberdi , Walter Alef , Keiichi Asada , Rebecca Azulay , David Ball , Mislav Balokovic , John Barrett , Dan Bintley , Lindy Blackburn , Wilfred Boland , Geoffrey C. Bower , Michael Bremer , Christiaan D. Brinkerink , Roger Brissenden , Silke Britzen , Dominique Broguiere , Thomas Bronzwaer , Do-Young Byun , John E. Carlstrom , Andrew Chael , Chi-kwan Chan , Shami Chatterjee , Koushik Chatterjee , Ming-Tang Chen , Yongjun Chen , Ilje Cho , John E. Conway , James M. Cordes , Geoffrey B. Crew , Yuzhu Cui , Jordy Davelaar , Mariafelicia De Laurentis , Roger Deane , Jessica Dempsey , Gregory Desvignes , Jason Dexter , Ralph P. Eatough , Heino Falcke , Vincent L. Fish , Ed Fomalont , Raquel Fraga-Encinas , Per Friberg , Christian M. Fromm , Charles F. Gammie , Roberto García , Olivier Gentaz , Ciriaco Goddi , Jose L. Gomez , Minfeng Gu , Mark Gurwell , Kazuhiro Hada , Ronald Hesper , Luis C. Ho , Paul Ho , Mareki Honma , Chih-Wei L. Huang , Lei Huang , David H. Hughes , Makoto Inoue , Sara Issaoun , David J. James , Buell T. Jannuzi , Michael Janssen , Wu Jiang , Alejandra Jimenez-Rosales , Michael D. Johnson , Svetlana Jorstad , Taehyun Jung , Mansour Karami , Ramesh Karuppusamy , Tomohisa Kawashima , Garrett K. Keating , Mark Kettenis , Jae-Young Kim , Junhan Kim , Jongsoo Kim , Motoki Kino , Jun Yi Koay , Patrick M. Koch , Shoko Koyama , Michael Kramer , Carsten Kramer , Thomas P. Krichbaum , Cheng-Yu Kuo , Tod R. Lauer , Sang-Sung Lee , Yan-Rong Li , Zhiyuan Li , Michael Lindqvist , Rocco Lico , Jun Liu , Kuo Liu , Elisabetta Liuzzo , Wen-Ping Lo , Andrei P. Lobanov , Colin Lonsdale , Ru-Sen Lu , Jirong Mao , Sera Markoff , Daniel P. Marrone , Alan P. Marscher , Ivan Martí-Vidal , Satoki Matsushita , Yosuke Mizuno , Izumi Mizuno , James M. Moran , Kotaro Moriyama , Monika Moscibrodzka , Cornelia Muller , Gibwa Musoke , Alejandro Mus Mejías , Hiroshi Nagai , Neil M. Nagar , Ramesh Narayan , Gopal Narayanan , Iniyan Natarajan , Roberto Neri , Aristeidis Noutsos , Hiroki Okino , Hector Olivares , Tomoaki Oyama , Daniel C. M. Palumbo , Jongho Park , Nimesh Patel , Ue-Li Pen , Vincent Pietu , Richard Plambeck , Aleksandar PopStefanija , Ben Prather , Jorge A. Preciado-Lopez , Venkatessh Ramakrishnan , Ramprasad Rao , Mark G. Rawlings , Alexander W. Raymond , Bart Ripperda , Freek Roelofs , Alan Rogers , Eduardo Ros , Mel Rose , Arash Roshanineshat , Helge Rottmann , Alan L. Roy , Chet Ruszczyk , Benjamin R. Ryan , Kazi L. J. Rygl , Salvador Sanchez , David Sanchez-Arguelles , Mahito Sasada , Tuomas Savolainen , F. Peter Schloerb , Karl-Friedrich Schuster , Lijing Shao , Zhiqiang Shen , Des Small , Bong Won Sohn , Jason SooHoo , Fumie Tazaki , Remo P. J. Tilanus , Michael Titus , Pablo Torne , Tyler Trent , Efthalia Traianou , Sascha Trippe , Ilse van Bemmel , Huib Jan van Langevelde , Daniel R. van Rossum , Jan Wagner , John Wardle , Derek Ward-Thompson , Jonathan Weintroub , Norbert Wex , Robert Wharton , Maciek Wielgus , George N. Wong , Qingwen Wu , Doosoo Yoon , Andre Young , Ken Young , Ziri Younsi , Feng Yuan , Ye-Fei Yuan , Shan-Shan Zhao , the EHT Collaboration

We investigate the impact of the modified gravity (MOG) field and the quintessence scalar field on horizon evolution, black hole (BH) shadow and the weak gravitational lensing around a static spherically symmetric BH. We first begin to…

General Relativity and Quantum Cosmology · Physics 2024-01-24 Ahmad Al-Badawi , Sanjar Shaymatov , Mirzabek Alloqulov , Anzhong Wang

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) has imaged the shadow of the supermassive black hole in M87. A library of general relativistic magnetohydrodynamics (GMRHD) models was fit to the observational data, providing constraints on black hole…

High Energy Astrophysical Phenomena · Physics 2021-06-09 Freek Roelofs , Christian M. Fromm , Yosuke Mizuno , Jordy Davelaar , Michael Janssen , Ziri Younsi , Luciano Rezzolla , Heino Falcke

This study investigates the effects of higher dimensions on the observable properties of Schwarzschild-Tangherlini black holes, focusing on the photonsphere, shadow radius, deflection angles, and quasinormal modes (QNMs). By extending…

General Relativity and Quantum Cosmology · Physics 2025-06-27 Nikko John Leo S. Lobos , Anele M. Ncube , Reggie C. Pantig , Alan S. Cornell

We investigate the astrophysical consequences of black holes in quadratic gravity, characterized by the parameters $S_0$, $S_2$, $m_0$ and $m_2$, in addition to the black hole mass $M$. To evaluate the physical validity of the fundamental…

General Relativity and Quantum Cosmology · Physics 2024-12-24 Somi Aktar , Niyaz Uddin Molla , Farook Rahaman , G. Mustafa

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

To explore the possible clues for the extra dimension from the Event Horizon Telescope (EHT) observations, we study the shadow of the rotating 5D black string in General Relativity (GR). Instead of investigating the shadow in the effective…

General Relativity and Quantum Cosmology · Physics 2022-11-16 Zi-Yu Tang , Xiao-Mei Kuang , Bin Wang , Wei-Liang Qian

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

In this study, we investigate black holes (BHs) surrounded by a quintessence field (QF) within the framework of effective quantum gravity (EQG). We analyze the spacetime metric characterized by quantum correction parameter $\xi$ and…

General Relativity and Quantum Cosmology · Physics 2025-03-25 Ahmad Al-Badawi , Faizuddin Ahmed , Tursunali Xamidov , Sanjar Shaymatov , İzzet Sakallı

The first images of black hole shadows open new possibilities to constrain modern extended gravity theories. We present the method of shadow background calculation for black hole solutions in the form of Taylor series where $g_{11} = -…

General Relativity and Quantum Cosmology · Physics 2022-09-07 V. Prokopov , S. Alexeyev , O. Zenin

Thanks for the releasing image of supermassive black holes (BHs) by the event horizon telescope (EHT) at the heart of the $M87$ galaxy. After the discovery of this mysterious object, scientists paid attention to exploring the BH shadow…

General Relativity and Quantum Cosmology · Physics 2023-03-01 Xiao-Xiong Zeng , M. Israr Aslam , Rabia Saleem

Motivated by recent work on the Modified Maxwell (ModMax) black holes [Phys.Lett.B 10.1016/j.physletb.2020.136011], which are invariant in duality rotations and conformal transformations founded in [ Phys.Rev.D 10.1103/PhysRevD.102.121703],…

General Relativity and Quantum Cosmology · Physics 2022-12-23 Reggie C. Pantig , Leonardo Mastrototaro , Gaetano Lambiase , Ali Övgün