The core-collapse rate from the Supernova Legacy Survey

Abstract

We use three years of data from the Supernova Legacy Survey (SNLS) to study the general properties of core-collapse and type Ia supernovae. This is the first such study using the "rolling search" technique which guarantees well-sampled SNLS light curves and good efficiency for supemovae brighter than i' ∼ 24. Using host photometric redshifts, we measure the supernova absolute magnitude distribution down to luminosities 4.5 mag fainter than normal SNIa. Using spectroscopy and light-curve fitting to discriminate against SNIa, we find a sample of 117 core-collapse supernova candidates with redshifts z < 0.4 (median redshift of 0.29) and measure their rate to be larger than the type Ia supernova rate by a factor 4.5 ± 0.8(stat.) ± 0.6(sys.). This corresponds to a core-collapse rate at z = 0.3 of [1.42 ± 0.3(stat.) ± 0.3(sys.)]*10-4 yr-1 (h-170 Mpc)-3. © ESO 2009.