Early light curves for Type Ia supernova explosion models

Upcoming high-cadence transient survey programmes will produce a wealth of observational data for Type Ia supernovae. These data sets will contain numerous events detected very early in their evolution, shortly after explosion. Together with a team led by Dr. Ulrich Nöbauer from the Max Planck Institute for Astrophysics,  we used numerical simulations to calculate synthetic observables for a number of different explosion models, specifically focusing on the first few days after explosion.

Synthetic light curves for various supernova explosion models in the Bessell U (upper left), B (upper right), V (lower left) and R (lower right) wavelength bands during the first 10 days after explosion. The inset shows the same curves on a logarithmic timescale. Credit: U. Nöbauer/MPA

Our results show that overall the early light curve evolution is similar for most of the investigated models. Characteristic imprints are induced by radioactive material located close to the surface. However, these  are very similar to the signatures expected from interactions between the SN ejecta and circumstellar material or a companion star. Apart from pure deflagration explosion models, none of the synthetic light curves exhibit the commonly assumed power-law rise. This can lead to substantial errors in the determination of the time of explosion. In summary, we illustrate with our calculations that even with very early data an identification of specific explosion scenarios is challenging, if only photometric observations are available. For more information see the research highlight at the Max Planck Institute for Astrophysics.

Paper published in Monthly Notices of the Royal Astronomical Society, Volume 472, Issue 3, Pages 2787–2799, full text available at https://arxiv.org/abs/1607.04081