The Core-collapse rate from the Supernova Legacy Survey

TL;DR

This study uses three years of Supernova Legacy Survey data to measure the core-collapse supernova rate, finding it significantly exceeds the Type Ia supernova rate at redshift 0.3, with well-sampled light curves and detailed host galaxy analysis.

Contribution

First use of the rolling search technique in SNLS to accurately measure the core-collapse supernova rate and analyze their properties relative to Type Ia supernovae.

Findings

Core-collapse supernova rate is 4.5 times higher than Type Ia rate at z=0.3.

Sample includes 117 core-collapse supernova candidates with z<0.4.

Measured core-collapse rate at z=0.3 as approximately 1.42 x 10^{-4} yr^{-1} Mpc^{-3}.

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 supernovae brighter than $i^\prime\sim24$. Using host photometric redshifts, we measure the supernova absolute magnitude distribution down to luminosities $4.5 {\rm mag}$ 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 $4.5\pm0.8(stat.) \pm0.6 (sys.)$. This corresponds to a core-collapse rate at $z=0.3$ of $[1.42\pm 0.3(stat.) \pm0.3(sys.)]\times10^{-4}\yr^{-1}(h_{70}^{-1}\Mpc)^{-3}$.