Speaker
Dr
Marc Betoule
(LPNHE CNRS IN2P3)
Description
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)
Co-authors
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)