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Related papers: Black Hole Shadows in Verlinde's Emergent Gravity

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In this paper, we re-evaluate the estimates of dust mass in galaxies and demonstrate that current dust models are incomplete and based on a priori assumptions. These models suffer from a circularity problem and account for only a small…

Astrophysics of Galaxies · Physics 2024-11-28 Václav Vavryčuk

Recent advances, including gravitational wave detections and imaging of black hole shadows, have strongly validated general relativity. Nevertheless, ongoing cosmological observations suggest potential limitations of general relativity,…

General Relativity and Quantum Cosmology · Physics 2025-08-11 Ali Övgün , Mohsen Fathi

To complement hydrodynamic studies of the tidal disruption of the star by a massive black hole, we present the study of stellar luminosity and its variations, produced by the strong gravitational field of the black hole during a close…

Astrophysics · Physics 2009-11-10 Andreja Gomboc , Andrej Cadez

We study lens statistics in flat, low-density universes with different equations of state $w=p_Q/\rho_Q$ for the dark energy component. Dark energy modifies the distance-redshift relation and the mass function of dark matter halos leading…

Astrophysics · Physics 2009-11-10 M. Kuhlen , C. R. Keeton , P. Madau

In rotating black hole background surrounded by dark matter, we investigated the super-radiant phenomenon of massive scalar field and its associated instability.Using the method of asymptotic matching, we computed the amplification factor…

General Relativity and Quantum Cosmology · Physics 2025-03-06 Quan-Xu Liu , Ya-Peng Hu , Tao-Tao Sui , Yu-Sen An

We study the shadow produced by a class of rotating black holes surrounded by plasma. The metric for these black holes arises by applying the Newman-Janis algorithm to a family of spherically symmetric spacetimes, which includes several…

General Relativity and Quantum Cosmology · Physics 2021-11-08 Javier Badía , Ernesto F. Eiroa

We analytically investigate the influence of a cosmic expansion on the shadow of the Schwarzschild black hole. We suppose that the expansion is driven by a cosmological constant only and use the Kottler (or Schwarzschild-deSitter) spacetime…

General Relativity and Quantum Cosmology · Physics 2018-06-05 Volker Perlick , Oleg Yu. Tsupko , Gennady S. Bisnovatyi-Kogan

The behavior of the angular velocity of a test particle moving in a stable circular orbit in the vacuum on the brane is considered. In the brane world scenario, the four dimensional effective Einstein equation acquire extra terms, called…

General Relativity and Quantum Cosmology · Physics 2008-11-26 C. G. Boehmer , T. Harko

A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a…

Astrophysics · Physics 2009-11-13 Stacy McGaugh

High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features…

Astrophysics · Physics 2007-05-23 Michael Gustafsson , Malcolm Fairbairn , Jesper Sommer-Larsen

It is well known that general relativity is an effective theory of gravity at low energy scale, and actually quantum effects cannot be ignored in the strong-field regime. As a strong gravitational object, black hole plays a key role in…

General Relativity and Quantum Cosmology · Physics 2022-03-23 Qi-Ming Fu , Xin Zhang

We investigate the null geodesic flow and in particular the light rings (LRs), fundamental photon orbits (FPOs) and shadows of a black hole (BH) immersed in a strong, uniform magnetic field, described by the Schwarzschilld-Melvin…

General Relativity and Quantum Cosmology · Physics 2021-08-17 Haroldo C. D. Lima Junior , Pedro V. P. Cunha , Carlos A. R. Herdeiro , Luís C. B. Crispino

The images of supermassive black holes surrounded by optically-thin, radiatively-inefficient accretion flows, like those observed with the Event Horizon Telescope, are characterized by a bright ring of emission surrounding the black-hole…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Ziri Younsi , Dimitrios Psaltis , Feryal Özel

Ambient dark matter (DM) around binary black holes can imprint characteristic signatures on gravitational waves emitted from their merger. The exact signature depends sensitively on the DM density profile around the black holes. We run very…

Astrophysics of Galaxies · Physics 2025-11-05 Shingo Hirano , Naoki Yoshida

Symmergent gravity is the $R+R^2$ gravity theory which emerges in a way restoring gauge symmetries broken explicitly by the ultraviolet cutoff in effective field theories. To test symmergent gravity we construct novel black hole solutions…

General Relativity and Quantum Cosmology · Physics 2021-11-09 İrfan Çimdiker , Durmuş Demir , Ali Övgün

In this paper, the shadows cast by non-rotating and rotating modified gravity black holes are investigated. In addition to the black hole spin parameter $a$ and the inclination angle $\theta$ of observer, another parameter $\alpha$…

General Relativity and Quantum Cosmology · Physics 2019-04-08 Hui-Min Wang , Yu-Meng Xu , Shao-Wen Wei

Detection of axion field can unfold intriguing facets of our universe in several astrophysical and cosmological scenarios. In four dimensions, such a field owes its origin to the completely anti-symmetric Kalb-Ramond field strength tensor.…

General Relativity and Quantum Cosmology · Physics 2020-06-11 Indrani Banerjee , Subhadip Sau , Soumitra SenGupta

We analysed the shadow cast by charged rotating black hole (BH) in presence of perfect fluid dark matter (PFDM). We studied the null geodesic equations and obtained the shadow of the charged rotating BH to see the effects of PFDM parameter…

General Relativity and Quantum Cosmology · Physics 2022-01-05 Farruh Atamurotov , Uma Papnoi , Kimet Jusufi

Limits on the dark matter fraction of small mass primordial black holes from Hawking radiation are predominantly derived from the assumption of a Schwarzschild black hole evaporating. However, astrophysical black holes are usually much more…

General Relativity and Quantum Cosmology · Physics 2026-04-03 Sebastian Schuster , Jessica Santiago , Justin Feng , Matt Visser

The so-called memory-burden effect implies that evaporating Primordial Black Holes (PBHs) inevitably stabilize before complete decay. This stabilization opens a new mass window for PBH Dark Matter below $10^{15}\,$g. The transition to the…

High Energy Physics - Phenomenology · Physics 2025-06-18 Alessandro Dondarini , Giulio Marino , Paolo Panci , Michael Zantedeschi
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