A 3D radiative transfer framework IX. Time dependence

TL;DR

This paper extends a 3D radiative transfer framework to include full time dependence of the radiation field, enabling more accurate modeling of dynamic astrophysical phenomena such as supernovae and stellar variability.

Contribution

The authors develop and implement a subvoxel method for incorporating the time derivative of the intensity into 3D radiative transfer calculations, advancing the modeling capabilities of the framework.

Findings

Validated the 3D time-dependent method against 1D results.

Demonstrated the method with a simple 3D test model.

Integrated the approach into PHOENIX/3D for broader use.

Abstract

Context. Time-dependent, 3D radiation transfer calculations are important for the modeling of a variety of objects, from supernovae and novae to simulations of stellar variability and activity. Furthermore, time-dependent calculations can be used to obtain a 3D radiative equilibrium model structure via relaxation in time. Aims. We extend our 3D radiative transfer framework to include direct time dependence of the radiation field; i.e., the $\partial I/ \partial t$ terms are fully considered in the solution of radiative transfer problems. Methods. We build on the framework that we have described in previous papers in this series and develop a subvoxel method for the $\partial I/\partial t$ terms. Results. We test the implementation by comparing the 3D results to our well tested 1D time dependent radiative transfer code in spherical symmetry. A simple 3D test model is also presented. Conclusions. The 3D time dependent radiative transfer method is now included in our 3D RT framework and in PHOENIX/3D.