The radial distribution of supernovae compared to star formation tracers
  Given the limited availability of direct evidence (pre-explosion
observations) for supernova (SN) progenitors, the location of supernovae (SNe)
within their host galaxies can be used to set limits on one of their most
fundamental characteristics, their initial progenitor mass. We present our
constraints on SN progenitors derived by comparing the radial distributions of
80 SNe in the SINGG and SUNGG surveys to the R-band, Halpha, and UV light
distributions of the 55 host galaxies. The strong correlation of Type Ia SNe
with R-band light is consistent with models containing only low mass
progenitors, reflecting earlier findings. When we limit the analysis of Type II
SNe to apertures containing 90 per cent of the total flux, the radial
distribution of these SNe best traces far ultraviolet (FUV) emission,
consistent with recent direct detections indicating Type II SNe have moderately
massive red supergiant progenitors. Stripped Envelope (SE) SNe have the
strongest correlation with Halpha fluxes, indicative of very massive
progenitors (M* > 20 M_solar). This result contradicts a small, but growing,
number of direct detections of SE SN progenitors indicating they are moderately
massive binary systems. Our result is consistent, however, with a recent
population analysis suggesting binary SE SN progenitor masses are regularly
underestimated. SE SNe are centralised with respect to Type II SNe and there
are no SE SNe recorded beyond half the maximum disc radius in the optical and
one third the disc radius in the ultraviolet. The absence of SE SNe beyond
these distances is consistent with reduced massive star formation efficiencies
in the outskirts of the host galaxies.
