I. A 3D externally illuminated slab benchmark for dust radiative transfer
Artikel i vetenskaplig tidskrift, 2017

Context. The radiative transport of photons through arbitrary three-dimensional (3D) structures of dust is a challenging problem due to the anisotropic scattering of dust grains and strong coupling between different spatial regions. The radiative transfer problem in 3D is solved using Monte Carlo or Ray Tracing techniques as no full analytic solution exists for the true 3D structures. Aims. We provide the first 3D dust radiative transfer benchmark composed of a slab of dust with uniform density externally illuminated by a star. This simple 3D benchmark is explicitly formulated to provide tests of the different components of the radiative transfer problem including dust absorption, scattering, and emission. Methods. The details of the external star, the slab itself, and the dust properties are provided. This benchmark includes models with a range of dust optical depths fully probing cases that are optically thin at all wavelengths to optically thick at most wavelengths. The dust properties adopted are characteristic of the diffuse Milky Way interstellar medium. This benchmark includes solutions for the full dust emission including single photon (stochastic) heating as well as two simplifying approximations: One where all grains are considered in equilibrium with the radiation field and one where the emission is from a single effective grain with size-distribution-averaged properties. A total of six Monte Carlo codes and one Ray Tracing code provide solutions to this benchmark. Results. The solution to this benchmark is given as global spectral energy distributions (SEDs) and images at select diagnostic wavelengths from the ultraviolet through the infrared. Comparison of the results revealed that the global SEDs are consistent on average to a few percent for all but the scattered stellar flux at very high optical depths. The image results are consistent within 10%, again except for the stellar scattered flux at very high optical depths. The lack of agreement between different codes of the scattered flux at high optical depths is quantified for the first time. Convergence tests using one of the Monte Carlo codes illustrate the sensitivity of the solutions to various model parameters. Conclusions. We provide the first 3D dust radiative transfer benchmark and validate the accuracy of this benchmark through comparisons between multiple independent codes and detailed convergence tests.


Spectral Energy-Distributions

Transfer Simulations

Edge-On Galaxies

radiative transfer

Young Stellar Objects



methods: numerical

Interstellar Clouds

Starburst Galaxies

ISM: general

Transfer Code



K. D. Gordon

Universiteit Gent

Space Telescope Science Institute (STScI)

Maarten Baes

Universiteit Gent

Simone Bianchi

Osservatorio Astrofisico di Arcetri

Peter Camps

Universiteit Gent

M. Juvela

Helsingin Yliopisto

R. Kuiper


Universität Tübingen

Tuomas Lunttila

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

K. A. Misselt

University of Arizona

G. Natale

University of Central Lancashire

T. Robitaille

Freelance Consultant


J. Steinacker

Centre national de la recherche scientifique (CNRS)

Université Grenoble Alpes


Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 603 A114- A114


Astronomi, astrofysik och kosmologi



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