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 …

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 …

The optical appearance of a body compact enough to feature an unstable bound orbit, when
surrounded by an accretion disk, is expected to be dominated by a luminous ring of radiation …

Gravitational lensing of a light source by a black hole leads to the appearance of higher-
order images produced by photons that loop around the black hole before reaching the …

Higher-order photon rings can be expected to be detected in a more detailed image of the
black hole found in future observations. These rings are lensed images of the luminous …

In this paper we study the gravitational lensing effect for the Schwarzschild solution with
holonomy corrections. We use two types of approximation methods to calculate the …

In this paper, we investigate the gravitational lensing effect for the Schwarzschild-like black
hole space-time in the background of a Kalb-Ramond (KR) field proposed by Yang et …

The effect of spacetime curvature on optical properties may provide an opportunity to
suggest new tests for gravity theories. In this paper, we investigated gravitational weak …

The dark matter halo has non-negligible effects on the gravitational lensing of supermassive
black hole in the galaxy center. Our work presents a study on the time-delay of light in …

The 0th order of affine perturbation series of the deflection angle of a ray near a photon
sphere is more accurate than a deflection angle in a strong deflection limit, which is used …