The impact of spiral density waves on the distribution of Supernovae
  We present an analysis of the impact of spiral density waves (DWs) on the
radial and surface density distributions of supernovae (SNe) in host galaxies
with different arm classes. We use a well-defined sample of 269 relatively
nearby, low-inclination, morphologically non-disturbed and unbarred Sa-Sc
galaxies from the Sloan Digital Sky Survey, hosting 333 SNe. Only for
core-collapse (CC) SNe, a significant difference appears when comparing their
R25-normalized radial distributions in long-armed grand-design (LGD) versus
non-GD (NGD) hosts, with that in LGD galaxies being marginally inconsistent
with an exponential profile, while SNe Ia exhibit exponential surface density
profiles regardless of the arm class. Using a smaller sample of LGD galaxies
with estimated corotation radii (Rc), we show that the Rc-normalized surface
density distribution of CC SNe indicates a dip at corotation. Although not
statistically significant, the high CC SNe surface density just inside and
outside corotation may be the sign of triggered massive star formation by the
DWs. Our results may, if confirmed with larger samples, support the large-scale
shock scenario induced by spiral DWs in LGD galaxies, which predicts a higher
star formation efficiency around the shock fronts, avoiding the corotation
region.
