Exploring the origins of Type Ia supernovae with Monte Carlo radiative transfer

In both scenarios, there are substantial departures from spherical symmetry. To constrain the viability of either scenario and understand the asymmetries, we have computed 3D photospheric- and 3D nebular-phase synthetic observables. At times around maximum light, the observable properties are comparable in both scenarios and resemble those of peculiar SNe la.

At late times, we find that the multidimensional structure of the models has a considerable influence on the overall ionisation balance and the width, velocity, and morphology of spectral features, which are sensitive to the observer's orientation. In the TwoExpl scenario, profiles such as the 8.991µm Ar III feature can appear somewhat flat-topped from some orientations and centrally peaked from others. Consequently, the current realisation of the OneExpl model represents a more plausible match to normal SNe la.

Our investigations demonstrate that the multidimensional structure of the explosion models is crucial for reconciling models with observational data. Further model realisations and space-based observations are needed to determine if either pathway is responsible for normal SNe la.