A 3D radiative transfer framework: VII. Arbitrary velocity fields in the Eulerian frame

TL;DR

This paper introduces a 3D radiative transfer method for arbitrary velocity fields in the Eulerian frame, implemented in the PHOENIX/3D code, enabling efficient large-scale astrophysical simulations.

Contribution

It presents a novel Eulerian approach for 3D radiative transfer with arbitrary velocities, compatible with existing computational frameworks.

Findings

Method is validated against 1D co-moving frame code.

Requires minimal additional memory.

Suitable for large-scale applications with thousands of wavelength points.

Abstract

A solution of the radiative-transfer problem in 3D with arbitrary velocity fields in the Eulerian frame is presented. The method is implemented in our 3D radiative transfer framework and used in the PHOENIX/3D code. It is tested by comparison to our well- tested 1D co-moving frame radiative transfer code, where the treatment of a monotonic velocity field is implemented in the Lagrangian frame. The Eulerian formulation does not need much additional memory and is useable on state-of-the-art computers, even large-scale applications with 1000's of wavelength points are feasible.