The Interaction of Supernova Ejecta with an Ambient Medium

Abstract

Plausible environments for supernovae are the interstellar medium with constant density or a circumstellar medium built up by mass loss with ρ ∝ r−n Self-similar solutions for the interaction region between the expanding supernova gas and the ambient gas exist provided that the expanding gas has ρ ∝ r−n with n > 5. The circumstellar medium case is likely to be important for the early evolution of Type II supernovae because their progenitor stars are probably red supergiants. The radio and X-ray emission observed from extragalactic supernovae may be from this interaction region. The early self-similar solutions can also be applied to the young galactic remnants.