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Calibration and inter-calibration of the SNLS and SDSS-II supernova survey

Apr 18, 2012, 2:40 PM


Impact of calibration errors on astrophysics parameters Session 3C


Dr Marc Betoule (LPNHE CNRS IN2P3)


With around 1 thousand type-Ia supernovae populating the Hubble diagram, the uncertainty of the photometric calibration of the survey now limits the precision of the cosmological parameters. We first present the method used to establish a uniform photometric response of the MegaCam instrument from CFHT used for SNLS. We then present a joint effort of the SNLS and SDSS collaborations to merge the photometric calibration of the two largest supernova surveys to date. Main products are a direct cross-calibration between the two surveys with a precision reaching 0.5%, a better understanding of the survey uniformity, and an improved absolute calibration with a redundant anchoring to the HST white dwarf system. We describe the method, dataset and results and discuss the remaining limitations and their origin.

Primary author

Dr Marc Betoule (LPNHE CNRS IN2P3)


Jean-Charles Cuillandre (Canada-France-Hawaii Telescope Corp.) John Marriner (Center for Particle Astrophysics, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510, USA) Julien Guy (LPNHE, CNRS-IN2P3 and Universités Paris 6 & 7) Nicolas Regnault (LPNHE, CNRS-IN2P3 and Universités Paris 6 & 7) Pierre Astier (LPNHE, CNRS-IN2P3 and Universités Paris 6 & 7)

Presentation materials