20 - Hunting for the signatures of 3-D explosions with 1-D synthetic spectra

Summary

Abstract

Multi-dimensional models of supernovae show radial and non-radial variation in the density and composition not seen in one-dimensional models. Many of the questions about the flow of radiation through the expanding, multi-dimensional atmosphere will require multi-dimensional radiation transport calculations, but some may be tested with existing one-dimensional transport codes. So far, tests with models of Type Ia supernovae have shown that the unburned fuel (C+O) mixed down into deeper layers in multi-dimensional models have only a simple (C II lines) and modest signature in the spectra. This places only light constraints on the mixing of C+O into the lower layers of Type Ia supernovae.

3-D effects on supernova spectra

The proliferation of multi-dimensional explosion models for supernovae has made it clear that using one dimensional models for spectrum synthesis is not fully adequate. How adequate are the old 1-D spectral models? What are the multidimensional signals present in the light received from distant supernovae? Can we calculate spectra with 1-D codes that can explore the multi-dimensional effects?

The clearest multi-dimensional signal in spectrum of supernova is polarization. The number of polarization observations of supernovae have increased dramatically in the last decade, and polarization has now been detected in all types and sub-types of supernovae. Since it is impossible to calculate polarization in the 1-D models we calculate, we will not discuss polarization further, but Kasen discusses polarization elsewhere in this volume.