Time‐dependent Monte Carlo Radiative Transfer Calculations for Three‐dimensional Supernova Spectra, Light Curves, and Polarization

We discuss Monte-Carlo techniques for addressing the 3-dimensionaltime-dependent radiative transfer problem in rapidly expanding supernovaatmospheres. The transfer code SEDONA has been developed to calculate thelightcurves, spectra, and polarization of aspherical supernova models. From theonset of free-expansion in the supernova ejecta, SEDONA solves the radiativetransfer problem self-consistently, including a detailed treatment of gamma-raytransfer from radioactive decay and with a radiative equilibrium solution ofthe temperature structure. Line fluorescence processes can also be treateddirectly. No free parameters need be adjusted in the radiative transfercalculation, providing a direct link between multi-dimensional hydrodynamicalexplosion models and observations. We describe the computational techniquesapplied in SEDONA, and verify the code by comparison to existing calculations.We find that convergence of the Monte Carlo method is rapid and stable even forcomplicated multi-dimensional configurations. We also investigate the accuracyof a few commonly applied approximations in supernova transfer, namely thestationarity approximation and the two-level atom expansion opacity formalism.Comment: 16 pages, ApJ accepte