159 articles – 2000 Notices  [english version]
 HAL : in2p3-00186269, version 1
 Code Bibliographique ADS : 2005AAS...207.1508N
 American Astronomical Society Meeting 207, Washington, DC : États-Unis
 SNLS: The Supernova Type Ia Rate at z = 0.47
 SNLS Collaboration(s)
 (2005)
 We present a preliminary measurement of the distant Type Ia supernova rate derived from the Canada -- France -- Hawaii Telescope Supernova Legacy Survey (SNLS). By observing four one-square degree fields with a high temporal frequency (< $\delta$ > ~4 observer-frame days) over large fractions of a year (~6 months each field, with breaks during full moon) and using 8 meter-class telescopes for spectroscopic followup, the survey not only provides the dense time sampling needed to achieve a high completeness, but also enjoys the benefit of high quality spectroscopy to verify the Type Ia candidates and hence reduce contamination from non-Type Ia events. The goal of the survey is to measure ~ 700 Type Ia SNe out to $z ^~ 1$ over a period of 5 years. We use the first two years of survey data to begin characterizing the Type Ia sample and explore a methodology for calculating rates from the survey. We use individual SNLS survey epoch properties to observe Monte Carlo simulations of $10^6$Type Ia supernovae in the redshift range 0.2 < z < 0.6, and thus derive our survey efficiency. We combine this efficiency with a carefully selected control sample of spectroscopically confirmed SNLS Type Ia SNe to derive a volumetric rate. When comparing our volumetric rate with other ground-based surveys that also use spectroscopic candidate verification, we find no evidence for significant systematic underestimation of the SN Ia rates near z = 0.5. When comparing published SN Ia rates spanning the redshift range 0.0 < z < 1.6 to models of SN Ia production, we find that neither pure delay-time models nor two component models can accommodate all the observed data.
 Thème(s) : Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
 in2p3-00186269, version 1 http://hal.in2p3.fr/in2p3-00186269 oai:hal.in2p3.fr:in2p3-00186269 Contributeur : Simone Lantz <> Soumis le : Jeudi 8 Novembre 2007, 15:18:43 Dernière modification le : Jeudi 8 Novembre 2007, 16:06:09