SIMBAD references

An increase in the number of studied Type Ia supernovae (SNe Ia) has demonstrated that this class of explosions has a greater diversity in its observables than was previously assumed. The reasons (e.g. the explosion mechanism, progenitor system) for such a diversity remain unknown. Here, we analyse a sample of r-band light curves of SNe Ia, focusing on their behaviour ∼2-4 weeks after maximum light, i.e. the second maximum. We characterize the second maximum by its timing (t_r2_) and the integrated flux (_r2_). We find that t_r2_ correlates with the 'colour-stretch' parameter s_BV , which can be used as a proxy for ⁵⁶Ni mass, and _r2_ correlates with the transparency time-scale, t₀. Using _r2_ for a sample of 199 SNe from the Palomar Transient Factory and intermediate Palomar Transient Factory, we evaluate a distribution on t₀ for a sample of SNe Ia found in an 'untargeted' survey. Comparing this distribution to the predictions of t₀ ranges from models we find that the largest overlap in t₀ values between models and observations is for the sub-Chandrasekhar double detonation models. We also compare our relations between t₀ and _r2_ with that from the 1D explosion models of Goldstein & Kasen and confirm that _r2_ can be used as a diagnostic of the total ejecta mass.