Shadows and weak gravitational lensing for black holes within Einstein-Maxwell-scalar theory*

Abstract

In this study, we investigated the optical properties of charged black holes within the Einstein-Maxwell-scalar (EMS) theory. We evaluated the shadow cast by these black holes and obtained analytical solutions for both the radius of the photon sphere and that of the shadow. We observed that black hole parameters γ and β both influence the shadow of black holes. We also found that the photon sphere and shadow radius increase as a consequence of the presence of the parameter γ. Interestingly, the shadow radius decreases first and then remains unchanged owing to the impact of the parameter β. Finally, we analyzed the weak gravitational lensing and total magnification of lensed images around black holes. We found that the charge of the black holes and the parameter β both have a significant impact, reducing the deflection angle. Similarly, the same behavior for the total magnification was observed, also as a result of the effect of the charge of the black holes and the parameter β.