Gamma-Ray Lines from Asymmetric Supernovae

Abstract

We present three-dimensional smoothed particle hydrodynamics simulations of supernova explosions from 100 s to 1 yr after core bounce. By extending our modeling efforts to a three-dimensional hydrodynamics treatment, we are able to investigate the effects of explosion asymmetries on mixing and γ-ray line emergence in supernovae. A series of initial explosion conditions are implemented, including jetlike and equatorial asymmetries of varying degree. For comparison, symmetric explosion models are also calculated. A series of time slices from the explosion evolution are further analyzed using a three-dimensional Monte Carlo γ-ray transport code. The emergent hard X- and γ-ray spectra are calculated as a function of both viewing angle and time, including trends in the γ-ray line profiles. We find significant differences in the velocity distribution of radioactive nickel between the symmetric and asymmetric explosion models. The effects of this spatial distribution change are reflected in the overall high-energy spectrum, as well as in the individual γ-ray line profiles.