Collisionless shocks and X-ray emission around supernova shock breakout

Abstract

We study analytically and numerically the formation of the collisionless shock around supernova shock breakout. Following core collapse, a radiation-dominated shock travels through the supernova progenitor. The collisionless shock (CS) is usually expected to form during breakout, when the radiation-dominated shock reaches the optically thin layers of the progenitor. In this work, we show that for some progenitors surrounded with optically thick winds, the collisionless shock forms before breakout. An X-ray flash would occur at shock breakout, even for 'slow' shocks. High-energy neutrinos with E 100 GeV − 1 TeV would precede the photon flash by typically a few minutes (Wolf-Rayet progenitors), up to ∼ 10 hours (red supergiants) [1].