DR. ROBERTO TROTTA

Supernovae type Ia (SNIa) are one of the observational pillars of the concordance cosmological model, and have been instrumental in determining the existence of dark energy. While the observational effort has been very successful in finding over 1,000 cosmologically useful SNIa's, the sophistication of statistical methods employed to analyse the data and infer cosmological parameters has been lagging behind. The speaker will present an overview of the status of SNIa cosmology, as well as new results from BAHAMAS (BAyesian HierArchical Modeling for the Analysis of Supernova cosmology), a fully Bayesian analysis of SNIa data, a demonstrably superior approach which improves on many shortcomings of the usual method. He will discuss how environmental effects in the SNIa's host galaxies must be taken into account in order to reduce systematic errors and to exploit upcoming large SNIa's data sets. He will present recent findings suggesting that the distance of the SNIa's to their host galaxy can be used to improve their usage as standard candles.