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Related papers: Can shadows connect black hole microstructures?

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We examine the observational discrepancies of two widely used models describing anisotropic (dark) matter distributions around a black hole, focusing on their photon spheres, shadow radii, and lensing observables. The models considered are…

General Relativity and Quantum Cosmology · Physics 2026-03-26 M. F. Fauzi , H. S. Ramadhan , A. Sulaksono

We consider spherically symmetric black holes with minimally coupled scalar fields and concentrate our attention on asymptotically flat self-gravitating configurations having the event horizons located at radii much smaller than $2m$. We…

General Relativity and Quantum Cosmology · Physics 2019-12-10 I. M. Potashov , Ju. V. Tchemarina , A. N. Tsirulev

In this paper, we examine the thermodynamic geometry of four-dimensional quasi-topological black holes by computing the Ruppeiner scalar curvature R which serves as an empirical tool to describe the nature of interactions among black hole…

General Relativity and Quantum Cosmology · Physics 2025-08-18 Apurba Tiwari , Randeep Kaur , Aruri Devaraju , Jaya Prakash Kode , Apparao Damarasingu , Silamanthula Hari Krishna , Akshay Gharat

We study the radiative properties of a spherical and singularity-free black-hole geometry recently proposed in the literature. Contrary to the Schwarzschild spacetime, this geometry is geodesically complete and regular, and, instead of the…

General Relativity and Quantum Cosmology · Physics 2025-07-23 Asier Alonso-Bardaji , David Brizuela , Marc Schneider

We have studied photon motion around axially symmetric rotating Kerr black hole in the presence of plasma with radial power-law density. It is shown that in the presence of plasma the observed shape and size of shadow changes depending on…

General Relativity and Quantum Cosmology · Physics 2015-10-21 Farruh Atamurotov , Bobomurat Ahmedov , Ahmadjon Abdujabbarov

We consider Kerr black holes (BHs) surrounded by perfect dark fluid matter (PFDM), with an additional parameter ($k$) because of PFDM, apart from mass ($M$) and rotation parameter ($a$) -- the rotating PFDM BHs. We analyze the photon orbits…

General Relativity and Quantum Cosmology · Physics 2023-02-22 Arshia Anjum , Misba Afrin , Sushant G. Ghosh

We study finite temperature correlation functions and quasinormal modes in a strongly coupled conformal field theory holographically dual to a small black hole in global Anti-de Sitter spacetime. Upon variation of the black hole radius, our…

High Energy Physics - Theory · Physics 2016-04-20 Niko Jokela , Arttu Pönni , Aleksi Vuorinen

We investigate the thermodynamics, criticality, and selected radiative and optical properties of an Euler-Heisenberg AdS black hole surrounded by quintessence, perfect fluid dark matter, and a cloud of strings. Within the extended…

General Relativity and Quantum Cosmology · Physics 2026-04-29 Faizuddin Ahmed , Edilberto O. Silva

The black hole photon ring is a prime target for upcoming space-based VLBI missions seeking to image the fine structure of astrophysical black holes. The classical Lyapunov exponents of the corresponding nearly bound null geodesics control…

General Relativity and Quantum Cosmology · Physics 2023-04-19 Daniel Kapec , Alexandru Lupsasca , Andrew Strominger

We study photon geodesics in topological solitons that have the same asymptotic properties as Schwarzschild black holes. These are coherent states in string theory corresponding to pure deformations of spacetime through the dynamics of…

General Relativity and Quantum Cosmology · Physics 2023-06-02 Pierre Heidmann , Ibrahima Bah , Emanuele Berti

This manuscript investigates a Schwarzschild black hole surrounded by perfect fluid dark matter embedded in a cloud of strings. The effects of its surroundings on thermodynamics, timelike and null geodesics, shadows, and quasinormal modes…

General Relativity and Quantum Cosmology · Physics 2025-03-28 Bilel Hamil , Bekir Can Lütfüoğlu

This paper investigates the dynamical behavior of steady spherical accretion onto a static, magnetically charged black hole embedded in a perfect fluid dark matter (PFDM) background. Using the shadow observations of M87* from the Event…

High Energy Astrophysical Phenomena · Physics 2026-03-11 Taiyang Zhang , Zhongyuan Qin , Qian Feng , Zheng-Wen Long

We obtain the shadow cast induced by the rotating black hole with an anisotropic matter. A Killing tensor representing the hidden symmetry is derived explicitly. The existence of separability structure implies a complete integrability of…

General Relativity and Quantum Cosmology · Physics 2021-03-24 Bum-Hoon Lee , Wonwoo Lee , Yun Soo Myung

In this essay we examine the gravitational collapse of a nonrelativistic charged perfect fluid interacting with a dark energy component. Given a simple factor for the energy transfer, we obtain a nonsingular interior solution which…

General Relativity and Quantum Cosmology · Physics 2026-05-15 Rodrigo Maier

We revisit static, spherically symmetric solutions to AdS-Einstein gravity with a conformally coupled scalar field (and no self-interaction potential) in four dimensions. We first observe that a convenient choice of coordinates leads to a…

General Relativity and Quantum Cosmology · Physics 2024-09-10 Marcello Ortaggio

We consider f(R) gravity theories in the presence of a scalar field minimally coupled to gravity with a self-interacting potential. When the scalar field backreacts to the metric we find at large distances scalarized Schwarzschild-AdS and…

General Relativity and Quantum Cosmology · Physics 2021-09-15 Zi-Yu Tang , Bin Wang , Thanasis Karakasis , Eleftherios Papantonopoulos

The optical appearance of a body compact enough to feature an unstable bound orbit, when surrounded by an accretion disk, is expected to be dominated by a luminous ring of radiation enclosing a central brightness depression typically known…

General Relativity and Quantum Cosmology · Physics 2023-09-25 Gonzalo J. Olmo , João Luís Rosa , Diego Rubiera-Garcia , Diego Sáez-Chillón Gómez

We investigated the shadow and optical appearance of Bardeen black hole (BH) immersed in perfect-fluid dark matter (PFDM). Using the EHT data, we find that the DM parameter is restricted to a narrow allowed range, confined to values of…

High Energy Astrophysical Phenomena · Physics 2025-12-02 Haiyuan Feng , Ziqiang Cai , Hao-Peng Yan , Rong-Jia Yang , Jinjun Zhang

We construct hairy black hole solutions that merge with the anti-de Sitter (AdS$_4$) Reissner-Nordstr\"om black hole at the onset of superradiance. These hairy black holes have, for a given mass and charge, higher entropy than the…

High Energy Physics - Theory · Physics 2017-03-02 Oscar J. C. Dias , Ramon Masachs

We study the optical appearance of a de Sitter-Schwarzschild black hole and its distinguishability from a Schwarzschild black hole. By exploring various accretion models and emission profiles, we investigate the impact of different…

General Relativity and Quantum Cosmology · Physics 2023-12-27 Zi-Liang Wang