Three Dimensional Continuum Radiative Transfer

Abstract

Radiative transfer is introduced as one of the grand challenge problems in astrophysics due to its key role of radiation as the main carrier of information and the high dimensionality of the problem. The relation to line RT is outlined and general solution methods are reviewed. We give the equation system for the stationary case of continuum radiation and discuss the different equation parts. As example for solution strategies, we discuss adaptively defined grids and ray-tracing algorithms dealing with high optical depth. The results of a two dimensional continuum RT benchmark are shown. Typical applications for continuum radiative transfer in star formation are presented in models for: (i) an evolving molecular cloud core as seen in SPH simulations and analyzed by forward RT calculations, (ii) SO-1 as largest circumstellar disk known so far, (iii) UC-1 as the first hypercompact HII region with a circumstellar disk candidate, (iv) IRS 15 as the first candidate for a remnant disk around a massive star, and (v) Rho Oph D where the inverse transfer modeling has led to the three dimensional density and dust temperature structure of the molecular cloud core.