The influence of line opacity treatment in STELLA on supernova light curves

TL;DR

This study investigates how different treatments of line opacity in the radiative transfer code STELLA affect supernova light curves across various types, emphasizing the importance of thermalisation in modeling accuracy.

Contribution

It systematically analyzes the impact of line opacity treatment and thermalisation parameters on supernova light curves using STELLA, supported by comparisons with spectral synthesis and observations.

Findings

Thermalisation parameter should be around 0.9 for accurate modeling.

Line opacity treatment significantly influences supernova light curve shapes.

The ratio of absorption to scattering varies between 0.8 and 1 for optimal results.

Abstract

We systematically explore the effect of the treatment of line opacity on supernova light curves. We find that it is important to consider line opacity for both scattering and absorption (i.e. thermalisation which mimics the effect of fluorescence.) We explore the impact of degree of thermalisation on three major types of supernovae: Type Ia, Type II-peculiar, and Type II-plateau. For that we use radiative transfer code STELLA and analyse broad-band light curves in the context of simulations done with the spectral synthesis code ARTIS and in the context a few examples of observed supernovae of each type. We found that the plausible range for the ratio between absorption and scattering in the radiation hydrodynamics code STELLA is (0.8-1):(0.2-0), i.e. the recommended thermalisation parameter is 0.9.