Speaker
Description
Type Ia supernovae (SNe Ia) have proved to be a successful probe of dark energy thanks to their property of standardizable candle allowing us to construct a supernova Hubble diagram with very low scatter through a two-parameter empirical light-curve correction. However, 0.15 magnitude intrinsic luminosity variation remains once corrections are applied, leaving plenty of room for a third variable correlating to Hubble diagram residuals. Indeed, the standardization process does not entirely capture the physical processes at play leading to the triggering of the explosion, and does not take into account the evolution of progenitor properties through history. In an attempt to link host galaxy properties to supernova light-curves, numerous independent studies have shown that host galaxy stellar masses significantly correlate with light-curve standardization parameters, and that Hubble diagram residuals correlate to global properties of the host galaxy. I present a consistent set of measurements of the properties of the global and local environments of type Ia supernovae in the largest spectroscopic sample to date. Our sample includes the full Supernova Legacy Survey data (SNLS) as well as the SDSS data and a number of well-measured low-redshift supernovae. While the analysis is still blinded regarding cosmology, preliminary results can be obtained which cast a new light on the environmental dependence of supernova luminosity.
