General spherically symmetric black bounces within non-linear electrodynamics

Abstract: Over the last years, the search of new regular black bounce solutions has drawn a lot of attentional over the international community working in gravitation. Indeed, in the era of gravitational waves detections out of binary mergers and of the imaging of the plasma around supermassive black holes, the study of everywhere regular solutions has become a common trend given the unique opportunity posed by multi-messenger astronomy to test deviations from the Kerr family of solutions. Among them, in this paper we consider the black bounce paradigm introduced by Simpson and Visser in [JCAP \textbf{02}, 042 (2019)], and provide a general procedure for reconstructing static spherically symmetric black bounce-type solutions that might interpolate between regular black holes and wormholes. We show that even after imposing some smoothness and flatness conditions on the metric components, additional analysis is required to obtain a well-defined black bounce solution. Then, the corresponding matter Lagrangian is reconstructed by using non-linear electrodynamics and the energy conditions are studied.