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Regular black hole is one of the bottom-up solutions designed to eliminate the singularity at the center of black holes. Its horizonless solution has gained interest recently to model ultracompact star. Despite interesting, this proposal is…

General Relativity and Quantum Cosmology · Physics 2024-11-26 M. F. Fauzi , H. S. Ramadhan , A. Sulaksono

We analyze the redshift suffered by photons originating from an external source, traversing a collapsing dust cloud and finally being received by an asymptotic observer. In addition, we study the shadow that the collapsing cloud casts on…

General Relativity and Quantum Cosmology · Physics 2015-09-10 Néstor Ortiz , Olivier Sarbach , Thomas Zannias

The study of black hole (BH) shadows provide crucial insights into the nature of strong gravitational effects and the intricate structure of the spacetime surrounding BHs. In this paper, we explore the shadow of Kerr MOG BH within a plasma…

General Relativity and Quantum Cosmology · Physics 2025-04-30 Saira Yasmin , Khadije Jafarzade , Mubasher Jamil

A black hole casts a shadow as an optical appearance because of its strong gravitational field. We study the shadow cast by the five-dimensional Myers-Perry black hole with equal rotation parameters. We demonstrate that the null geodesic…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Uma Papnoi , Farruh Atamurotov , Sushant G. Ghosh , Bobomurat Ahmedov

We investigate the shadow cast by a sort of new regular black holes which are characterized by an asymptotically Minkowski core and the Sub-Planckian curvature. Firstly, we extend the metric with spherical symmetry to the one of rotating…

General Relativity and Quantum Cosmology · Physics 2022-11-17 Yi Ling , Meng-He Wu

The relation between the black hole shadow and the black hole thermodynamics is investigated. We find that the phase structure can be reflected by the shadow radius for the spherically symmetric black hole. We also find that the shadow size…

General Relativity and Quantum Cosmology · Physics 2020-08-28 Ming Zhang , Minyong Guo

In this paper, we derive general conditions for a shadow to occur, without a photon sphere in a spacetime, caused by central nulllike or timelike naked singularities. Using these conditions, we propose classes of spacetimes which have…

General Relativity and Quantum Cosmology · Physics 2021-01-13 Dipanjan Dey , Rajibul Shaikh , Pankaj S. Joshi

We study the shadows of the fully non-linear, asymptotically flat Einstein-dilaton-Gauss-Bonnet (EdGB) black holes (BHs), for both static and rotating solutions. We find that, in all cases, these shadows are smaller than for comparable Kerr…

General Relativity and Quantum Cosmology · Physics 2017-03-22 Pedro V. P. Cunha , Carlos A. R. Herdeiro , Burkhard Kleihaus , Jutta Kunz , Eugen Radu

Recently the Event Horizon Telescope observed black holes at event horizon scales for the first time, enabling us to now test the existence of event horizons. Although event horizons have by definition no observable features, one can look…

General Relativity and Quantum Cosmology · Physics 2024-09-18 Joost de Kleuver , Thomas Bronzwaer , Heino Falcke , Ramesh Narayan , Yosuke Mizuno , Oliver Porth , Hector Olivares

In general relativity, isolated black holes are invisible due to an infinitely large redshift of photons propagating from the event horizon to the remote observer. However, the dark shadow (silhouette) of a black hole can be visible on the…

General Relativity and Quantum Cosmology · Physics 2020-08-31 Vyacheslav I. Dokuchaev , Natalia O. Nazarova

A black hole embedded within a bright, optically thin emitting region imprints a nearly circular "shadow" on its image, corresponding to the observer's line-of-sight into the black hole. The shadow boundary depends on the black hole's mass…

High Energy Astrophysical Phenomena · Physics 2020-09-09 Joseph R. Farah , Dominic W. Pesce , Michael D. Johnson , Lindy L. Blackburn

Using the Hamilton-Jacobi method, we study certain optical shadows of rotating Bardeen-AdS black holes in the presence of internal and external field contributions. Precisely, we examine the shadow using one-dimensional real curves. By…

General Relativity and Quantum Cosmology · Physics 2022-04-13 Adil Belhaj , Hajar Belmahi , Mohamed Benali , Hasan El Moumni , Mohammed Amine Essebani , Moulay Brahim Sedra

We study the shadow of rotating charge black holes in the presence of quintessence. The shadow of a rotating black hole is a distorted circle and in our study, we find that the shape and size of the black hole shadow depend upon four…

General Relativity and Quantum Cosmology · Physics 2022-05-05 Balendra Pratap Singh

We study the possibility of identifying dark matter in the galactic center from the physical properties of the electromagnetic radiation emitted from a optical-thin disk region around a static and spherically symmetric black hole. In…

General Relativity and Quantum Cosmology · Physics 2021-06-03 Saurabh , Kimet Jusufi

The shadow of a black hole is usually calculated, either analytically or numerically, on the assumption that the black hole is eternal, i.e., that it existed for all time. Here we ask the question of how this shadow comes about in the…

General Relativity and Quantum Cosmology · Physics 2018-05-15 Stefanie Schneider , Volker Perlick

Pushed by a number of advances, electromagnetic observatories have now reached the horizon scale of supermassive black holes. The existence and properties of horizons in our universe is one of the outstanding fundamental issues that can now…

General Relativity and Quantum Cosmology · Physics 2022-08-16 João Luís Rosa , Paulo Garcia , Frédéric H. Vincent , Vitor Cardoso

The motion of photons around the Kerr-Newman-dS black hole surrounded by quintessence and a cloud of strings is investigated. The existence of the Carter constant leads to that of unstable circular photon orbits on a two-dimensional plane…

General Relativity and Quantum Cosmology · Physics 2023-10-31 Wen-Fu Cao , Wen-Fang Liu , Xin Wu

We investigate black holes with non-minimal couplings between the electromagnetic field and spacetime curvature, focusing on their event horizons, shadows, and photon rings. Such couplings can naturally arise from both classical effective…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Zhixiang Yin , Changjun Gao , Yun-Long Zhang

Can the observation of the "shadow" allow us to distinguish a black hole from a more exotic compact object? We study the motion of photons in a class of vacuum static axially-symmetric space-times that is continuously linked to the…

General Relativity and Quantum Cosmology · Physics 2019-07-12 Askar B. Abdikamalov , Ahmadjon A. Abdujabbarov , Dimitry Ayzenberg , Daniele Malafarina , Cosimo Bambi , Bobomurat Ahmedov

The silhouette of a black hole having a critical curve (an unstable bound photon orbit) when illuminated by an optically thin accretion disk whose emission is confined to the equatorial plane shows a distinctive central brightness…

General Relativity and Quantum Cosmology · Physics 2022-05-11 Merce Guerrero , Gonzalo J. Olmo , Diego Rubiera-Garcia , Diego Sáez-Chillón Gómez