Multi-messenger emission from choked jets in collapsars

The death of massive stars is accompanied by the formation of central and accreting compact objects and the subsequent launch of relativistic jets. However, not all jets successfully drill their way out of the stellar envelope. %which would result in gamma-ray emission. Unsuccessful jets, also known as choked jets, may still produce radiation at lower frequencies by dissipating the jet energy into a pressurized cocoon. This cocoon expands within the stellar envelope and eventually breaks out as a mildly relativistic outflow. We investigate the plasma physics in the surroundings of massive collapsing stars harboring choked jets via radiative, relativistic, non-resistive MHD simulations. As a result, we define the parameter space allowing for jets to remain choked, and we quantify the acceleration rate and efficiency for charged particles in the strong shocks of such astrophysical environments. Preliminary results show that high Mach numbers (~ 100) after 10-15 seconds of constant energy injection are sufficient to accelerate particles at energies capable of generating high-energy neutrinos. Our results are presented for various stellar progenitors, including red and blue supergiants.