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Related papers: Apparent shape of super-spinning black holes

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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 study the gravitational lensing by a Kerr-Sen Black Hole arising in heterotic string theory. A closed form expression for the bending angle of light in equatorial plane of Kerr-Sen Black Hole is derived as a function of impact parameter,…

General Relativity and Quantum Cosmology · Physics 2018-05-24 Rashmi Uniyal , Hemwati Nandan , Philippe Jetzer

Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at a TeV and the observed weakness of gravity at long distances is due…

High Energy Physics - Theory · Physics 2009-10-31 Philip C. Argyres , Savas Dimopoulos , John March-Russell

Black holes of mass M must have a spin angular momentum S below the Kerr limit chi = S/M^2 < 1, but whether astrophysical black holes can attain this limiting spin depends on their accretion history. Gas accretion from a thin disk limits…

General Relativity and Quantum Cosmology · Physics 2010-12-21 Michael Kesden , Guglielmo Lockhart , E. Sterl Phinney

Black hole (BH) spins in low-mass X-ray binaries (LMXBs) cover a range of values that can be explained by accretion after BH birth. In contrast, the three BH spin measurements in high-mass X-ray binaries (HMXBs) show only values near the…

Solar and Stellar Astrophysics · Physics 2019-01-23 Ying Qin , Pablo Marchant , Tassos Fragos , Georges Meynet , Vicky Kalogera

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

It has been shown that ultraenergetic collisions can occur near the horizon of an extremal Kerr black hole. Previous studies mainly focused on geodesic motions of particles. In this paper, we consider spinning test particles whose orbits…

General Relativity and Quantum Cosmology · Physics 2016-05-04 Minyong Guo , Sijie Gao

Magnetically charged black holes (MBHs) are interesting solutions of the Standard Model and general relativity. They may possess a "hairy" electroweak-symmetric corona outside the event horizon, which speeds up their Hawking radiation and…

High Energy Physics - Phenomenology · Physics 2021-03-11 Yang Bai , Joshua Berger , Mrunal Korwar , Nicholas Orlofsky

The tidal acceleration experienced by an object at the event horizon of a black hole decreases as one over the square of the black hole's mass. As such there is a maximum mass at which a black hole can tidally disrupt an object outside of…

General Relativity and Quantum Cosmology · Physics 2024-02-13 Andrew Mummery

Due to the gravitational lensing effect, a black hole casts a shadow larger than its horizon over a bright background, and the shape and size can be calculated. The Event Horizon Telescope collaboration has produced the first direct image…

General Relativity and Quantum Cosmology · Physics 2021-09-28 Rahul Kumar , Balendra Pratap Singh , Md Sabir Ali , Sushant G. Ghosh

Light bosonic degrees of freedom have become a serious candidate for dark matter. The evolution of these fields around curved spacetimes is poorly understood but is expected to display interesting effects. In particular, the interaction of…

General Relativity and Quantum Cosmology · Physics 2013-02-20 Helvi Witek , Vitor Cardoso , Akihiro Ishibashi , Ulrich Sperhake

The recent detection of gravitational waves from black hole coalescences and the first image of the black hole shadow enhance the possibilities of testing gravitational theories in the strong-field regime. In this paper, we study the…

General Relativity and Quantum Cosmology · Physics 2020-05-27 Che-Yu Chen

Stellar mass black holes (SMBHs), forming by the core collapse of very massive, rapidly rotating stars, are expected to exhibit a high density accretion disk around them developed from the spinning mantle of the collapsing star. A wide…

High Energy Astrophysical Phenomena · Physics 2013-08-07 Indrani Banerjee , Banibrata Mukhopadhyay

In a previous paper, one of us has showed that, at least in some cases, the Kerr-nature of astrophysical black hole candidates is extremely difficult to test and current techniques, even in presence of excellent data not available today,…

General Relativity and Quantum Cosmology · Physics 2014-01-28 Zilong Li , Cosimo Bambi

The No Hair theorem in classical general relativity predicts that rotating black holes are specified by the Kerr metric, which is uniquely identified by the mass and spin. However, as a pioneering study beyond general relativity, the…

General Relativity and Quantum Cosmology · Physics 2023-04-26 Zhen Li

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

Light bending by the strong gravity around the black hole will form the so-called black hole shadow, the shape of which can shed light on the structure of the near-horizon geometry to possibly reveal novel physics of strong gravity and…

General Relativity and Quantum Cosmology · Physics 2022-09-28 Feng-Li Lin , Avani Patel , Hung-Yi Pu

We construct a family of non-supersymmetric extremal black holes and their horizonless microstate geometries in four dimensions. The black holes can have finite angular momentum and an arbitrary charge-to-mass ratio, unlike their…

High Energy Physics - Theory · Physics 2021-10-20 Ibrahima Bah , Iosif Bena , Pierre Heidmann , Yixuan Li , Daniel R. Mayerson

We report and comment upon the principal results of an investigation into the evolution of rotating black holes emitting massless scalar radiation via the Hawking process. It is demonstrated that a Kerr black hole evaporating by the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Chris M. Chambers , William A. Hiscock , Brett E. Taylor

We present the metric for a rotating black hole with a cosmological constant and with arbitrary angular momenta in all higher dimensions. The metric is given in both Kerr-Schild and Boyer-Lindquist form. In the Euclidean-signature case, we…

High Energy Physics - Theory · Physics 2010-04-06 G. W. Gibbons , H. Lu , D. N. Page , C. N. Pope