Radiation Hydrodynamics in Astrophysics

Abstract

Hydrodynamics codes are used to study nearly every astrophysical phenomena observed. Although coupling radiation and hydrodynamics is much less common, radiation hydrodynamics codes are being used in a growing number of astrophysics problems from energetic out flows of compact remnants such as core-collapse supernovae and active galactic nuclei to the formation of stars and planets to cosmological simulations of the first stars. In this paper, we review the current “state-of-the-art” radiation hydrodynamics techniques used in astrophysics. This review will cover both the techniques used in astrophysics (Sect. 2) and the problems that have been studied (Sect. 3). Most of the techniques are well-known in both the transport and hydrodynamics communities. The only surprises may be the rudemenatry level at which most working astrophysics codes do radiation transport. In Sect. 4, we will study in more detail the method used to do radiation hydrodynamics with smooth particle hydrodynamics, as it is less well-known and may prove a powerful tool to solve a number of astrophysics problems. What astrophysicists mean when they say they have a “radiation hydrodynamics” code varies from person to person. So before we begin this review, we must go through a few definitions.