Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A

S Vagnozzi, R Roy, YD Tsai, L Visinelli… - … and Quantum Gravity, 2023 - iopscience.iop.org
Horizon-scale images of black holes (BHs) and their shadows have opened an
unprecedented window onto tests of gravity and fundamental physics in the strong-field …

Nonlinear electrodynamics effects on the black hole shadow, deflection angle, quasinormal modes and greybody factors

M Okyay, A Övgün - Journal of Cosmology and Astroparticle …, 2022 - iopscience.iop.org
In this paper, we discuss the effects of nonlinear electrodynamics (NED) on non-rotating
black holes, parametrized by the field coupling parameter β and magnetic charge parameter …

Superradiant evolution of the shadow and photon ring of Sgr

Y Chen, R Roy, S Vagnozzi, L Visinelli - Physical Review D, 2022 - APS
Ultralight bosons can affect the dynamics of spinning black holes (BHs) via superradiant
instability, which can lead to a time evolution of the supermassive BH shadow. We study …

Deriving weak deflection angle by black holes or wormholes usingGauss-Bonnet theorem

Y Kumaran, A Övgün - Turkish Journal of Physics, 2021 - journals.tubitak.gov.tr
In this review, various researches on finding the bending angle of light deflected by a
massive gravitating object which regard the Gauss-Bonnet theorem as the premise have …

Superradiance evolution of black hole shadows revisited

R Roy, S Vagnozzi, L Visinelli - Physical Review D, 2022 - APS
Black hole (BH) shadows can be used to probe new physics in the form of ultralight particles
via the phenomenon of superradiant instability. By directly affecting the BH mass and spin …

[HTML][HTML] Shadow, lensing, quasinormal modes, greybody bounds and neutrino propagation by dyonic ModMax black holes

RC Pantig, L Mastrototaro, G Lambiase… - The European Physical …, 2022 - Springer
Motivated by recent work on the Modified Maxwell (ModMax) black holes [Phys Lett B
10.1016/j. physletb. 2020.136011], which are invariant in duality rotations and conformal …

Probing a non-linear electrodynamics black hole with thin accretion disk, shadow, and deflection angle with M87* and Sgr A* from EHT

A Uniyal, RC Pantig, A Övgün - Physics of the Dark Universe, 2023 - Elsevier
Non-linear interaction between the electromagnetic fields (EMF) occurs when vacuum
polarization in quantum electrodynamics (QED) happens. The field of non-linear …

Black holes with scalar hair in light of the Event Horizon Telescope

M Khodadi, A Allahyari, S Vagnozzi… - Journal of Cosmology …, 2020 - iopscience.iop.org
Searching for violations of the no-hair theorem (NHT) is a powerful way to test gravity, and
more generally fundamental physics, particularly with regards to the existence of additional …

Gravitational deflection of light and shadow cast by rotating Kalb-Ramond black holes

R Kumar, SG Ghosh, A Wang - Physical Review D, 2020 - APS
The nonminimal coupling of the nonzero vacuum expectation value of the self-interacting
antisymmetric Kalb-Ramond field with gravity leads to a power-law hairy black hole having a …

Gravitational lensing by black holes in the 4D Einstein-Gauss-Bonnet gravity

SU Islam, R Kumar, SG Ghosh - Journal of Cosmology and …, 2020 - iopscience.iop.org
Recently, a non-trivial 4D Einstein-Gauss-Bonnet (EGB) theory of gravity, by rescaling the
GB coupling parameter as α/(D− 4), was formulated in [1], which bypasses Lovelock's …