The radial distribution of Type Ia supernovae in early-type galaxies:: implications for progenitor scenarios

We study the radial distribution of Type Ia supernovae (SNe Ia) in morphologically selected early-type host galaxies from the Sloan Digital Sky Survey (SDSS) and discuss its implications for the progenitor systems of SNe Ia. While new observations of early-type galaxies suggest that they contain small fractions of young stellar populations, they are also the most likely hosts for long time-delay SNe Ia. We find that there is no statistically significant difference between the radial distribution of SNe Ia and the light profile of their early-type host galaxies, which are dominated by old, metal-rich stellar populations. This confirms the commonly accepted idea that some SN Ia progenitors have time delays of the order of several Gyr.