Cavity in the hypernova ejecta of GRB 190114C.
Ruffini R., Melon Fuksman J.D., Vereshchagin G.V.
III - Astrofisica
GSSI Ex ISEF - Aula D - Venerdì 27 h 15:30 - 19:00
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Within the binary-driven hypernova 1 (BdHN 1) scenario, the gamma-ray burst GRB190114C originates in a binary system composed of a massive carbon-oxygen core, and a binary neutron star companion. As the CO core undergoes a supernova explosion with the creation of a new neutron star, hypercritical accretion occurs onto the companion binary neutron star until it exceeds the critical mass for gravitational collapse. The formation of a black hole captures baryons by enclosing them within its horizon, and thus a cavity around it. A further depletion of baryons in the cavity originates from the expansion of the electron-positron-photon plasma formed at the collapse. It is demonstrated here using an analytical model complemented by a hydrodynamical numerical simulation that part of the plasma is reflected off the walls of the cavity. The consequent outflow and its observed properties are shown to coincide with the featureless emission occurring in a time interval of duration, measured in the rest frame of the source, between 11 and 20 s of the GBM observation.