Mar 06, 2013

Daan va Rossum

"Modeling Type Ia Supernova Light Curves and Spectra: Achieving Higher Fidelity"

Supernovae of Type Ia (SN Ia) show light curves with very typical rising-falling behaviour.  Although the rough rising-falling shape is easy to reproduce, the high standards set by modern observational data are hard to meet with even the most sophisticated radiation transport models.  Accuracy in calculated light curves and spectra is essential for understanding the SN Ia explosion mechanism and helping observers make SNe Ia better standard candles for cosmology.
I will address three important challenges encountered in modern SN Ia radiation transport calculations.  First, I will describe a new method for evolving the energy balance over time in stellar atmosphere codes.  This new method greatly improves on current methods in accuracy and is physically self-consistent.  I then present the first /pure/ NLTE light curves and spectra and compare them with LTE and semi-NLTE results.  Finally, I will show how new model spectra reveal that the nature of many spectral features in SN Ia spectra is slightly different than commonly believed.