WEAK GRAVITATIONAL LENSING BY CHARGED BLACK HOLES

Abstract

The deflection of light due to gravity was predicted by general relativity and first confirmed by observations in 1919. In the following decades, various aspects of the gravitational lensing effect were theoretically explored, including the possibility of obtaining multiple or annular images of background sources, the use of lensing as a gravitational telescope on very faint and distant objects, and the possibility of determining the Hubble constant using lensing. Gravitational lensing is the deflection of light by gravity caused by the action of compact astrophysical objects. Various objects, such as a galaxy, stars, black holes, wormholes, and others, can act as a gravitational lens. In our study, as a gravitational lens, we chose black holes described by the Gibbons-Maeda-GarfinkleHorowitz-Strominger solutions in the string frame. The two solutions in the string frame are magnetically and electrically charged black holes with an event horizon. The work will investigate the effect of electric and magnetic charges on the angle of deflection of light.