- Neill, JD
- Sullivan, M
- Balam, D
- Pritchet, CJ
- Howell, DA
- Perrett, K
- Astier, P
- Aubourg, E
- Basa, S
- Carlberg, RG
- Conley, A
- Fabbro, S
- Fouchez, D
- Guy, J
- Hook, I
- Pain, R
- Palanque-Delabrouille, N
- Regnault, N
- Rich, J
- Taillet, R
- Aldering, G
- Antilogus, P
- Arsenijevic, V
- Balland, C
- Baumont, S
- Bronder, J
- Ellis, RS
- Filiol, M
- Gonçalves, AC
- Hardin, D
- Kowalski, M
- Lidman, C
- Lusset, V
- Mouchet, M
- Mourao, A
- Perlmutter, S
- Ripoche, P
- Schlegel, D
- Tao, C
- et al.
We present a measurement of the distant Type la supernova (SN Ia) rate derived from the first 2 yr of the Canada-France-Hawaii Telescope Supernova Legacy Survey. We observed four 1° × 1° fields with a typical temporal frequency of (Δt) ∼ 4 observer-frame days over time spans of 158-211 days per season for each field, with breaks during the full Moon. We used 8-10 m class telescopes for spectroscopic follow-up to confirm our candidates and determine their redshifts. Our starting sample consists of 73 spectroscopically verified SNe la in the redshift range 0.2 < z < 0.6. We derive a volumetric SN Ia rate of r (〈z〉 = 0.47) = [0.42 (syst.) ± 0.06(stat.)] × 10 yr Mpc , assuming h = 0.7, Ω -0.3, and a flat cosmology. Using recently published galaxy luminosity functions derived in our redshift range, we derive a SN Ia rate per unit luminosity of r (〈z〉 = 0.47) = 0.154 (syst.) (stat.) SN units. Using our rate alone, we place an upper limit on the component of SN la production that tracks the cosmic star formation history of 1 SN la per 10 M of stars formed. Our rate and other rates from surveys using spectroscopic sample confirmation display only a modest evolution out to z = 0.55. © 2006. The American Astronomical Society. All rights reserved. V 0.09 m L -0.033 0.031 ⊙ 0.13 -4 -1 3 0.048 0.039 3