In this study, we review some current studies on gravitational lensing for black holes, mainly
in the context of general relativity. We mainly focus on the analytical studies related to …

In order to clarify the effects of the finite distance from a lens object to a light source and a
receiver, the gravitational deflection of light has been recently reexamined by using the …

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 …

We discuss a possible extension of calculations of the bending angle of light in a static,
spherically symmetric and asymptotically flat spacetime to a nonasymptotically flat case. We …

By using the Gauss-Bonnet theorem, the bending angle of light in a static, spherically
symmetric and asymptotically flat spacetime has been recently discussed, especially by …

We investigate the equatorial deflection angle of light rays propagating in Kerr-Newman
black-bounce spacetime. Furthermore, we analyze the light ray trajectories and derive a …

Continuing work initiated in an earlier publication [A. Ishihara, Y. Suzuki, T. Ono, T. Kitamura,
and H. Asada, Phys. Rev. D 94, 084015 (2016). PRVDAQ 2470-0010 10.1103/PhysRevD …

Gravitational lensing by the light sphere of compact objects like black holes and wormholes
will give us information on the compact objects. In this paper, we provide an improved strong …

Observations of gravitational lenses in strong gravitational fields give us a clue to
understanding dark compact objects. In this paper, we extend a method to obtain a …

We investigate gravitational lensing by a photon sphere in a Reissner-Nordström naked
singularity spacetime in strong deflection limits. Because of the nonexistence of an event …