Comparisons of the radial distributions of core-collapse supernovae with those of young and old stellar populations

We present observational constraints on the nature of core-collapse (CC) supernovae (SNe) through an investigation into their radial distributions with respect to those of young and old stellar populations within their host galaxies, as traced by Hα emission and R-band light, respectively. We discuss results and the implications they have on the nature of SN progenitors, for a sample of 177 CC SNe.

We find that the radial positions of the overall CC population closely follow the radial distribution of Hα emission, implying that both are excellent tracers of star formation within galaxies. Within this overall distribution, we find that there is a central deficit of SNII which is offset by a central excess of SNIb/c. This implies a strong metallicity dependence on the relative production of the two types, with SNIb/c arising from higher metallicity progenitors than SNII. Separating the SNIb/c into individual classes, we find that a trend emerges in terms of progenitor metallicity going from SNII through SNIb to SNIc, with the latter arising from the highest metallicity progenitors.

Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Institute de Astrofísica de Canarias, and on observations made with the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias with financial support from the UK Science and Technology Facilities Council.

E-mail: anderson@das.uchile.cl