Flavor compostion of neutrinos originated in choked gamma-ray bursts

REYNOSO, MATIAS M.; DEUS, FLORENCIA A.

San Juan, Argentina

Encuentro; 65 Reunion Anual de la Asociación Argentina de Astronomía; 2023

Facultad de Ciencias Exáctas Físicas y Naturales, UNSJ ? CONICET

Choked gamma-ray bursts (CGRBs) are produced when the jet generatedin the center of a massive collapsing star fails to emerge from the stellar envelope, and hence the gamma rays produced in such a jet get absorbed. Neutrinos, however, escape freely, and therefore these sources that have been proposed as capable of generating the diffuse flux observed by IceCube. In the present work, we aim to obtain the neutrino fluxes of thedifferent flavors corresponding to CGRBs under different assumptions for the soft photon density and the magnetic field in the emission region. We then consider the injection of both protons and electrons, which are assumed to be accelerated by internal shocks in the jet. By solving a steady-state transport equation, we obtain the particle distributions,including also pions, kaons, and muons, since these particles are generated after copious pγ interactions in the present context. Considering that CGRBs can be related to core collapse supernovae, we assume that the generation rate of these sources is proportional to thestar formation rate, and we integrate on the redshift to obtain a total diffuse neutrino flux of each flavor. The flavor composition to be observed at the Earth is found to depend on the energy as a consequence of the losses suffered mainly by pions and muons: for energies above ∼ (10^5 − 10^6) GeV (depending on the magnetic field, proton-to-electron ratio, andjet power) the electron flavor ratio is found to decrease and the muon one to increase, while the tau flavor ratio increases only moderately. This will be probed with next generation neutrino instruments such as IceCube-gen2.