STRONG GRAVITATIONAL LENSING FOR THE CASE OF NO HORIZON REGULAR CHARGED BLACK HOLES

Abstract

Gravitational lensing often becomes one of the ways to experimentally test a particular theory of gravity, since it allows a visual comparison of theoretical predictions with observational data. The more massive the compact object, the stronger the visible effects are; for this reason, it seems very promising to study strong gravitational lensing by sources such as supermassive black holes. The aim of this paper is to study gravitational lensing for the case of spherically symmetric regular charged black holes with 0 < b ≤ bE and compare the obtained parameters with those calculated for spacetime without a horizon ( b > bE). Here b is an additional parameter describing the charge, and its value b = bE = 0.226 corresponds to the boundary case when the horizon disappears. In addition, using the massive objects Phe A* and M104* as an example, as well as the elliptical galaxies NGC57 and NGC163, we will compare the observed characteristics of regular charged and ordinary Schwarzschild black holes: the angular position of the asymptotic relativistic images, the angular distance between them and those calculated for the same b most images that are farthest from the center, as well as zooming in on the farthest images. The results obtained can later be compared with observational data, which will allow us to conclude that the approach used is applicable within the framework of the theory under consideration.