A Central Excess of Stripped-Envelope Supernovae within Disturbed
  Galaxies
  This paper presents an analysis of core-collapse supernova distributions in
isolated and interacting host galaxies, paying close attention to the selection
effects involved in conducting host galaxy supernova studies. When taking into
account all of the selection effects within our host galaxy sample, we draw the
following conclusions: i) Within interacting, or 'disturbed', systems there is
a real, and statistically significant, increase in the fraction of
stripped-envelope supernovae in the central regions. A discussion into what may
cause this increased fraction, compared to the more common type IIP supernovae,
and type II supernovae without sub-classifications, is presented. Selection
effects are shown not to drive this result, and so we propose that this study
provides direct evidence for a high-mass weighted initial mass function within
the central regions of disturbed galaxies. ii) Within 'undisturbed' spiral
galaxies the radial distribution of type Ib and type Ic supernovae is
statistically very different, with the latter showing a more centrally
concentrated distribution. This could be driven by metallicity gradients in
these undisturbed galaxies, or radial variations in other properties (binarity
or stellar rotation) driving envelope loss in progenitor stars. This result is
not found in 'disturbed' systems, where the distributions of type Ib and Ic
supernovae are consistent.
