Early light curves for Type Ia supernova explosion models

Abstract

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. Here, we present synthetic light curves, calculated with the radiation hydrodynamical approach Stella for a number of different explosion models, specifically focusing on these first few days after explosion. We 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 ejecta-CSM or ejecta-companion interaction. Apart from the pure deflagration explosion models, none of our synthetic light curves exhibit the commonly assumed power-law rise. We demonstrate that 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.

Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

“…Specifically, Noebauer et al (2017) examine two Chandrasekhar-mass (M Ch ) explosions and compare their evolution to sub-Chandrasekhar detonations and pure deflagrations. The M Ch explosions include the "W7" carbon-deflagration model of Nomoto et al (1984) and the "N100" delayed-detonation model from Seitenzahl et al (2013).…”

“…The sub-Chandrasekhar models include a violent WD-WD merger, which triggers a carbon detonation in the more massive WD, a centrally ignited sub-Chandrasehkar detonation, and a sub-Chandrasehkar double-detonation explosion, in which an He-surface-layer detonation triggers a carbon detonation in the core. Noebauer et al (2017) note that, of these last two sub-Chandrasehkar models, the latter provides the more realistic scenario. Finally, Noebauer et al also examine the "N5def" and "N1600Cdef" pure deflagration explosions from Fink et al (2014).…”

“…In Figure 9 we compare photometric observations of iPTF 16abc to the models presented in Noebauer et al (2017).…”

“…As a brief aside, we note that simulations presented in Noebauer et al (2017) show that SN Ia explosion models do not evolve as a power law in time. Noebauer et al demonstrate that f t µ a fits to simulated light curves result in glaring errors to the estimated explosion times.…”

“…Noebauer et al demonstrate that f t µ a fits to simulated light curves result in glaring errors to the estimated explosion times. While caution is advised in Noebauer et al (2017), we note that our primary aim with the power-law fit is to characterize α for iPTF 16abc compared to SN 2011fe.…”