Abstract:

Type Ia supernovae prove to be the most precise cosmological distance indicators. Based on simple models with essentially only one free parameter describing the entire family of Type Ia supernova, distances as accurate as 4-8% can be deduced. An embarrassing situation is, however, that we are still far from understanding how Type Ia supernovae explode. For more precise cosmological experiments, the simple one-parameter models are apparently inappropriate. I will discuss new numerical methods for quantifying multi-color Type Ia light curves. The new methods can significantly improve the use of Type Ia supernovae as standard distance indicators. The evolution of the properties of Type Ia supernovae is a potential threat to supernova cosmology. I will show evidence that supernova properties do depend on the age of their host galaxies, but they are not sensitive to the initial metallicity of the progenitor stars. Instead, turbulence and chemical mixing during explosive nuclear burning are the most important systematic effects that need to be studied in detail for the next generation supernova cosmology.