Simulating short gamma-ray burst jets with genuine surrounding environments.

GRB 170817A provided clear evidence of an intrinsic connection between short gamma-ray bursts (SGRBs) and binary neutron star (BNS) mergers. The mechanism by which the latter are able to feed the former, however, remains poorly understood, and many theoretical and phenomenological models, combining observational data with results of numerical calculations, are currently under development with the aim of unveiling it. In this talk, I will present results of numerical simulations in which we modelled, for the first time, the three-dimensional evolution of an SGRB jet propagating through the post-merger environment of a fully general-relativistic (GR) hydrodynamic BNS merger simulation, reaching space-time scales relevant for the gamma-ray emission, and providing self-consistent predictions for the jet's final structure and energetics. I will also discuss the ongoing work concerning the inclusion of magnetic fields in our jet simulations, directly importing magnetized initial data from GR magneto-hydrodynamic BNS merger simulations.