Vol. 553
In section 3. Cosmology

Spectrophotometric time series of SN 2011fe from the Nearby Supernova Factory

The authors present a remarkable, publicly available spectrophotometric time series (3300-9700 A) for the SN Ia 2011fe in M 101, beginning at only about 2.6 days after the projected time of the explosion and extending for more than 114 days (97 days after peak visual magnitude) with high cadence (between one and three days). From this they produce synthetic light curves in standard filters that can be used to evaluate the various contributions to the photometric variations during the early expansion and that they then compare with published photometric data sets. Important is that they confirm there was no reddening of SN 2011fe from dust in M 101. Thus they can construct a bolometric light curve from which they derive a 56Ni mass of 0.55+/-0.11 solar mass. They also show velocity curves for important optical lines (e.g. Si II 5640, 6355, and C II 6580) and model fits to the ensemble of spectra that they compare with other recent NSF observations. The study is a benchmark standard for calibrating higher-z SN Ia and will be a fundamental reference for all future studies.