The rate of supernovae at redshift 0.1–1.0^⋆,⋆⋆

The Stockholm VIMOS Supernova Survey III

¹ Department of Astronomy, Oskar Klein CentreStockholm University, AlbaNova University Centre, 10691 Stockholm, Sweden
e-mail: jens@astro.su.se
² Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
³ Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland
⁴ CNRS, Université de Toulouse, UPS-OMP, IRAP, 31028 Toulouse, France
⁵ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany

Received: 7 April 2012
Accepted: 20 July 2012

Abstract

We present supernova rate measurements at redshift 0.1–1.0 from the Stockholm VIMOS Supernova Survey (SVISS). The sample contains 16 supernovae in total. The discovered supernovae have been classified as core collapse or type Ia supernovae (9 and 7, respectively) based on their light curves, colour evolution and host galaxy photometric redshift. The rates we find for the core collapse supernovae are 3.29_-1.78 -1.45^+3.08 +1.98 × 10^-4 yr^-1 Mpc^-3 h₇₀³ (with statistical and systematic errors respectively) at average redshift 0.39 and 6.40_-3.12 -2.11^+5.30 +3.65 × 10^-4 yr^-1 Mpc^-3 h₇₀³ at average redshift 0.73. For the type Ia supernovae we find a rate of 1.29_-0.57 -0.28^+0.88 +0.27 × 10^-4 yr^-1  Mpc^-3 h₇₀³ at ⟨z⟩ = 0.62. All of these rate estimates have been corrected for host galaxy extinction, using a method that includes supernovae missed in infrared bright galaxies at high redshift. We use Monte Carlo simulations to make a thorough study of the systematic effects from assumptions made when calculating the rates and find that the most important errors come from misclassification, the assumed mix of faint and bright supernova types and uncertainties in the extinction correction. We compare our rates to other observations and to the predicted rates for core collapse and type Ia supernovae based on the star formation history and different models of the delay time distribution. Overall, our measurements, when taking the effects of extinction into account, agree quite well with the predictions and earlier results. Our results highlight the importance of understanding the role of systematic effects, and dust extinction in particular, when trying to estimate the rates of supernovae at moderate to high redshift.