Radiative cooling in numerical astrophysics: the need for adaptive mesh refinement

TL;DR

This paper discusses the importance of adaptive mesh refinement in numerical astrophysics to accurately simulate radiative cooling, which introduces numerical challenges requiring high resolution and specialized treatment.

Contribution

It highlights the necessity of adaptive mesh refinement for effectively modeling radiative cooling in astrophysical simulations, addressing associated numerical challenges.

Findings

Radiative cooling significantly affects gas dynamics in astrophysics.

High resolution via adaptive mesh refinement is essential for accurate simulations.

Semi-implicit methods are needed to handle cooling timescales.

Abstract

Energy loss through optically thin radiative cooling plays an important part in the evolution of astrophysical gas dynamics and should therefore be considered a necessary element in any numerical simulation. Although the addition of this physical process to the equations of hydrodynamics is straightforward, it does create numerical challenges that have to be overcome in order to ensure the physical correctness of the simulation. First, the cooling has to be treated (semi-)implicitly, owing to the discrepancies between the cooling timescale and the typical timesteps of the simulation. Secondly, because of its dependence on a tabulated cooling curve, the introduction of radiative cooling creates the necessity for an interpolation scheme. In particular, we will argue that the addition of radiative cooling to a numerical simulation creates the need for extremely high resolution, which can only be fully met through the use of adaptive mesh refinement.