Supernova feedback and the energy deposition in molecular clouds

Abstract

Feedback from supernovae is often invoked as an important process in limiting star formation, removing gas from galaxies and, hence, as a determining process in galaxy formation. Here, we report on numerical simulations, investigating the interaction between supernova explosions and the natal molecular cloud. We also consider the cases with and without previous feedback from the high-mass star in the form of ionizing radiation and stellar winds. The supernova is able to find weak points in the cloud and creates channels through which it can escape, leaving much of the well-shielded cloud largely unaffected. This effect is increased when the channels are preexisting due to the effects of previous stellar feedback. The expanding supernova deposits its energy in the gas that is in these exposed channels, and, hence, sweeps up less mass when feedback has already occurred, resulting in faster outflows with less radiative losses. The full impact of the supernova explosion is then able to impact the larger scale of the galaxy in which it abides. We conclude that supernova explosions have only moderate effects on their dense natal environments but that with preexisting feedback, the energetic effects of the supernova are able to escape and affect the wider scale medium of the galaxy.