Gamma-Ray Lines from Asymmetric Supernovae

TL;DR

This paper uses 3D simulations to study how asymmetries in supernova explosions affect gamma-ray emissions and element mixing, revealing significant differences from symmetric models.

Contribution

It introduces 3D hydrodynamics and gamma-ray transport modeling to analyze the impact of explosion asymmetries on supernova spectra and element distribution.

Findings

Asymmetric explosions show different nickel velocity distributions.

Gamma-ray line profiles vary with explosion asymmetry and viewing angle.

Spectral differences are linked to spatial distribution changes of radioactive materials.

Abstract

We present 3-dimensional SPH simulations of supernova explosions from 100 seconds to 1 year after core-bounce. By extending our modelling efforts to a 3-dimensional hydrodynamics treatment, we are able to investigate the effects of explosion asymmetries on mixing and gamma-ray line emergence in supernovae. A series of initial explosion conditions are implemented, including jet-like 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 3-dimensional Monte Carlo gamma-ray transport code. The emergent hard X- and gamma-ray spectra are calculated as a function of both viewing angle and time, including trends in the gamma-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 gamma-ray line profiles.