Speaker: Marc Betoule (France)
Recent cosmological analyses from type Ia supernovae face the limitation of measurement systematics and cannot fully exploits the high statistics gathered in latest SN-Ia surveys. By reaching sub-percent accuracy in the relative flux calibration of the two main SNe surveys (SNLS and SDSS-II), we decreased the level of systematics, enabling to take full advantage of 3 years of the SNLS and SDSS-II data. We also performed detailed investigations of other important systematics associated to the SN-Ia light-curve model and survey selection biases.
Our joint sample delivers the most sensitive constraints on Dark Energy to date, and is found compatible with a cosmological constant. In combination with the recent CMB measurement from Planck, we obtain a measurement of the constant equation of state parameter w in a flat universe with an accuracy better than 6%.