Gravitational lensing by $k-n$ generalized black-bounce space-times

Abstract

We study gravitational lensing by $k-n$ generalized black-bounce space-times both in regimes of weak and strong field approximations. These metrics interpolate between regular black holes and one-way or traversable wormholes. First, we investigate the light-like geodesic trajectories and derive an analytical expression for the deflection angle in terms of the bounce parameter in the weak-field gravitational regime. We then turn to the strong-field gravitational regime and display the behavior of the bending angle as a function of both the impact parameter and the bounce parameter. Next, using the lens equations, we analyze how the observables for \textit{Sagittarius} A* behave concerning the bounce parameter. We obtain the shadow's radii for some black-bounce metrics and plot the graph of their sizes, comparing them with the Schwarzschild one.