Résumé / Abstract Journal-club_Hautes_Energies

Journal-club Hautes Energies

« The role of jet-cocoon mixing, magnetization and shock breakout in neutrino and cosmic-ray emission from short GRBs »

Ore Gottlieb
Departement of Astrophysics, Tel Aviv University (Tel Aviv, Israël)

Gamma-ray bursts (GRBs) are considered to be leading candidates of the cosmic-ray (CR) and neutrino production in the universe. To date, all studies estimated the CR and neutrino fluxes from GRBs analytically, ignoring the complex evolution of GRB jets and their interaction with the surrounding medium. We provide the first estimate for neutrino and cosmic-ray (CR) signals from self-consistent GRMHD and RMHD simulations of GRBs in neutron star mergers. We show that the mixing between the jet and the cocoon, which is present in all types of jets, inhibits the formation of subphotospheric collisionless shocks, contrary to previous results. However, it is shown that a mild magnetization may lead to the formation of collisionless subshocks which allow efficient proton acceleration. Considering shear acceleration and diffusive shock acceleration at collimation shocks, internal shocks, shock breakout and external shocks, we find that short GRBs do not produce detectable neutrino signals with current-day facilities. Using the numerical modeling that fits GW170817 afterglow emission, we find that blast waves in BNS mergers can account for 5%-10% of the Galactic CR luminosity in the PeV-EeV energy range.
jeudi 27 mai 2021 - 13:30
Webinaire, Institut d'Astrophysique
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