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 …

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 …

[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 …

[HTML][HTML] Wormhole solutions in symmetric teleparallel gravity

G Mustafa, Z Hassan, P Moraes, PK Sahoo - Physics Letters B, 2021 - Elsevier
In this letter we obtain wormhole solutions from the Karmarkar condition in f (Q) gravity
formalism, in which Q is the nonmetricity scalar. We show that the combination of such …

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 …

Strong gravitational lensing and shadow constraint from M87* of slowly rotating Kerr-like black hole

XM Kuang, A Övgün - Annals of Physics, 2022 - Elsevier
Motivated by (i) more and more interest in strong gravitational lensing by supermassive
black holes due to the achievement of EHT observations,(ii) the ongoing popular topic on …

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 …

Testing dynamical torsion effects on the charged black hole's shadow, deflection angle and greybody with M87* and Sgr. A* from EHT

RC Pantig, A Övgün - Annals of Physics, 2023 - Elsevier
Poincaré Gauge's theory of gravity is the most noteworthy alternative extension of general
relativity that has a correspondence between spin and spacetime geometry. In this paper …