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Related papers: A Lensing-Band Approach to Spacetime Constraints

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With a semiclassical polymerization in the loop quantum gravity (LQG), the interior of Schwarzschild black holes provides a captivating single-horizon regular black hole spacetime. The shortage of rotating black hole models in loop quantum…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Jitendra Kumar , Shafqat Ul Islam , Sushant G. Ghosh

The emission region and black hole shadow of Sagittarius A*, the supermassive black hole at the Galactic Center, can be probed with millimeter Very Long Baseline Interferometry. Our goal is to probe the geometry of the emitting plasma…

Astrophysics of Galaxies · Physics 2016-03-23 R. Fraga-Encinas , M. Moscibrodzka , C. Brinkerink , H. Falcke

Direct detection of gravitational waves and binary black hole mergers have proven to be remarkable investigations of general relativity. In order to have a definitive answer as to whether the black hole spacetime under test is the Kerr or…

General Relativity and Quantum Cosmology · Physics 2024-04-03 Abhishek Chowdhuri , Arpan Bhattacharyya , Shailesh Kumar

The no-hair theorem characterizes the fundamental nature of black holes in general relativity. This theorem can be tested observationally by measuring the mass and spin of a black hole as well as its quadrupole moment, which may deviate…

High Energy Astrophysical Phenomena · Physics 2016-08-24 Tim Johannsen

We investigate strong gravitational lensing using magnetized Kerr black holes (MKBHs), which are accurate Kerr-Bertotti-Robinson solutions for Kerr black holes in a uniform magnetic field with additional magnetic field strength $B$ apart…

General Relativity and Quantum Cosmology · Physics 2026-01-28 Amnish Vachher , Arun Kumar , Sushant G. Ghosh

In this work, we study the gravitational lensing by a Lorentz-violating (LV) black hole inspired by the recent contribution [1]. Explicitly, we concentrate on a specific application: we perform the computation of gravitational lensing…

General Relativity and Quantum Cosmology · Physics 2025-11-21 A. A. Araújo Filho , J. R. Nascimento , A. Yu. Petrov , P. J. Porfírio

X-ray studies of stellar mass black holes in X-ray binaries and mass-accreting supermassive black holes in Active Galactic Nuclei have achieved a high degree of maturity and have delivered detailed information about the astrophysical…

High Energy Astrophysical Phenomena · Physics 2018-07-26 Henric Krawczynski

Recent observations indicate that many if not all galaxies host massive central black holes. In this paper we explore the influence of black holes on the lensing properties. We model the lens as an isothermal ellipsoid with a finite core…

Astrophysics · Physics 2009-10-31 S. Mao , H. J. Witt , L. V. E. Koopmans

Very long baseline interferometry (VLBI) provides the highest-resolution images in astronomy. The sharpest resolution is nominally achieved at the highest frequencies, but as the observing frequency increases so too does the atmospheric…

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

Astrophysical black hole candidates are thought to be the Kerr black holes predicted by General Relativity, but the actual nature of these objects has still to be proven. The Kerr black hole hypothesis can be tested by observing strong…

General Relativity and Quantum Cosmology · Physics 2017-02-17 Cosimo Bambi

Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still…

A key obstacle for theory-specific tests of general relativity is the lack of accurate black-hole solutions in beyond-Einstein theories, especially for moderate to high spins. We address this by developing a general framework--based on…

General Relativity and Quantum Cosmology · Physics 2026-01-19 Kelvin Ka-Ho Lam , Adrian Ka-Wai Chung , Nicolás Yunes

According to the general-relativistic no-hair theorem, astrophysical black holes depend only on their masses and spins and are uniquely described by the Kerr metric. Mass and spin are the first two multipole moments of the Kerr spacetime…

High Energy Astrophysical Phenomena · Physics 2016-05-27 Tim Johannsen

This work is an extensive literature review focusing on a few of the important topics in the large-scale structure of spacetime. The work is a Bachelor's thesis submitted at the Institute of Theoretical Physics, University of Leipzig. The…

General Relativity and Quantum Cosmology · Physics 2019-11-18 Rohan Kulkarni

The X-ray emission of neutron stars and black holes presents a rich phenomenology that can lead us to a better understanding of their nature and to address more general physics questions: Does general relativity apply in the strong gravity…

In this work, gravitational lensing in the weak and strong field limits is investigated for black hole spacetime within the framework of Hu-Sawicki $f(R)$ gravity. We employ the Ishihara et al. approach for weak lensing and adopt Bozza's…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Gayatri Mohan , Nashiba Parbin , Umananda Dev Goswami

Recent developments in very long baseline interferometry (VLBI) have made it possible for the Event Horizon Telescope (EHT) to resolve the innermost accretion flows of the largest supermassive black holes on the sky. The sparse nature of…

Very long baseline interferometry (VLBI) makes it possible to recover images of astronomical sources with extremely high angular resolution. Most recently, the Event Horizon Telescope (EHT) has extended VLBI to short millimeter wavelengths…

Instrumentation and Methods for Astrophysics · Physics 2018-02-05 Katherine L. Bouman , Michael D. Johnson , Adrian V. Dalca , Andrew A. Chael , Freek Roelofs , Sheperd S. Doeleman , William T. Freeman

One of the scientific objectives of the Laser Interferometer Space Antenna (LISA) is to probe the expansion of the Universe using gravitational wave observations. Indeed, as gravitational waves from the coalescence of a massive black hole…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-17 Alberto Mangiagli , Chiara Caprini , Sylvain Marsat , Lorenzo Speri , Robert R. Caldwell , Nicola Tamanini
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