Transient High-energy Gamma-Rays and Neutrinos from Nearby Type II Supernovae

A dense wind environment (or circumstellar medium) may be ubiquitous in regular Type II supernovae (SNe II) before explosion, the interaction of which with the SN ejecta could result in a wind breakout event. The shock generated by the interaction of the SN ejecta and the wind can accelerate protons and subsequently high-energy gamma-rays and neutrinos could arise from inelastic pp collisions. In this work, we present detailed calculations of gamma-ray and neutrino production for regular SNe II. The calculations are executed by applying time-dependent evolution of dynamic and proton distributions so that the emission can be shown at different times. Our results show, for the SN 2013fs-like wind environment, multi-GeV and a few hundred TeV gamma-rays are detectable with a time window of several days at less than or similar to 2-3 Mpc by Fermi/LAT and the Cerenkov Telescopes Array during the ejecta-wind interaction, respectively, and can be detected at a further distance if the wind environment is denser. We find the contribution of wind breakouts of regular SNe II to diffusing neutrino flux is subdominant by assuming all SNe II are SN 2013fs-like, whereas for a denser wind environment the contribution could be conspicuous above 300 TeV.