Stéphane Blondin : The width-luminosity relation for Type Ia supernovae: physical origin and implications for cosmology

lundi 23 mai 2016, 14:00 → 15:00 Europe/Paris

Type Ia supernovae (SNe Ia) are thought to result from the thermonuclear disruption of a carbon-oxygen white dwarf (WD) star as it approaches the Chandrasekhar-mass limit. The empirical width-luminosity relation for SNe Ia revolutionized the use of these stellar explosions as extra-galactic distance indicators and formed the cornerstone of the discovery of dark energy. However, the physical origin of this relation is still debated, as is its connection to the progenitor properties and explosion mechanisms of SNe Ia. I will present recent results of radiative-transfer simulations of such events, which show that the width-luminosity relation can be reproduced by theoretical models only when considering SN Ia progenitors significantly below the Chandrasekhar mass. This has important consequences for the use of these events to constrain cosmological parameters over a large redshift range, as will be done for instance by future surveys with the Large Synoptic Survey Telescope (LSST).