Statistics of extragalactic supernovae

It is shown that supernovae of Type II are concentrated in spiral arms, whereas those of Type I show no preference for spiral-arm regions. Rediscussion of available supernova statistics suggests that Tammann (1970) may have overestimated the dependence of supernova frequency on galaxy inclination. A study of the distribution of supernovae in elliptical galaxies indicates that the supernova rate per unit luminosity may be highest among (possibly metal-poor) stars in the halos of E galaxies. All galaxies in which supernovae are known to have occurred have been classified on the DDO system.