Deflection of Light and Shadow Cast by a Dual Charged Stringy Black Hole

Abstract

Gravitational lensing and black hole shadows are one of the strongest observational evidences to prove the existence of black holes in the universe. The gravitational lensing arises due to the deflection of light by the gravitational field of a gravitating body such as a black hole. Investigation of the shadow cast by a compact object as well as deflection of light around it may provide the useful information about physical nature of the particular compact object and other related aspects. In this paper, we study the deflection of light by a dual charged stringy black hole spacetime derived in dilaton-Maxwell gravity. The variation of deflection angle with the impact parameter for different values of electric and magnetic charges is studied. We also study the shadow of this black hole spacetime to obtain the radius of shadow cast by it. We have considered an optically thin emission disk around it and observed that there are not significant changes in the shadow cast by this black hole compared to well-known Schwarzschild black hole spacetime in GR.