Multidimensional radiative transfer calculations of the light curves and spectra of Type Ia supernovae

Abstract

The explosion of a white dwarf star in a Type Ia supernova (SN Ia) explosion leads to the burning and ejection of stellar material at a few percent of the speed of light. The spectacle we observe in the months that follow is from the leaking of radiation from this glowing mass of radioactive debris. The modeling of SN Ia light curves and spectra represents a complex problem in time-dependent radiative transfer. Here we discuss numerical methods, in particular Monte Carlo methods, for calculating 3D multi-wavelength radiative transport on massively parallel machines. Our approach involves a newly developed domain decomposition technique in which the memory load is distributed over multiple processors and photon packets are communicated from node to node. We present results for 2-dimensional models that explore white dwarf explosions over a range of explosion paradigms and ignition conditions. These models give insight into how variations in the initial conditions of the explosion affect the light curve we finally observe. We conclude with an outlook (and some initial results) for large scale 3D radiation transport calculations of SNe Ia in an era of petascale computing.