Supernova feedback and the energy deposition in molecular clouds
  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 ionising radiation and stellar winds. The supernova is able to
find weak points in the cloud and create channels through which it can escape,
leaving much of the well shielded cloud largely unaffected. This effect is
increased when the channels are pre-existing 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 only
have moderate effects on their dense natal environments but that with
pre-existing feedback, the energetic effects of the supernova are able to
escape and affect the wider scale medium of the galaxy.
