The core-collapse rate from the Supernova Legacy Survey

¹ CEA/Saclay, DSM/Irfu/Spp, 91191 Gif-sur-Yvette Cedex, France e-mail: rich@hep.saclay.cea.fr
² APC, UMR 7164 CNRS, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
³ LPNHE, CNRS-IN2P3 and Universities of Paris 6 & 7, 75252 Paris Cedex 05, France
⁴ University Paris 11, 91405 Orsay, France
⁵ LAM, CNRS, BP8, Pôle de l'étoile, Site de Château-Gombert, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France
⁶ Deparment of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8, Canada
⁷ CPPM, CNRS-Luminy, Case 907, 13288 Marseille Cedex 9, France
⁸ University of Oxford, Astrophysics, Denys Wilkinson Building, Kneble Road, Oxford OX1 3RH, UK
⁹ Department of Physics and Astronomy, University of Victoria, PO Box 3055, Victoria, BC V8W 3P6, Canada
¹⁰ CENTRA-Centro M. de Astrofisica and Department of Physics, IST, Lisbon, Portugal
¹¹ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile
¹² LUTH, UMR 8102 CNRS, Observatoire de Paris, Section de Meudon, 92195 Meudon Cedex, France

Received: 13 February 2009
Accepted: 6 April 2009

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 ~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( Mpc)^-3.