The SKIRT project
advanced radiative transfer for astrophysics
Polarization from scattering in an axisymmetric dust disk

Introduction

Pinte et al. 2009 present a 2D continuum radiative transfer benchmark that includes the effects of polarization for anisotropic scattering by spherical dust grains. The test configuration is a star embedded in a circumstellar disk with an inner cavity free of dust. This configuration is similar to that used by Pascucci et al. 2004 (Axisymmetric circumstellar dust disk) but it has a smaller central cavity and a steeper radial density gradient, making the problem more difficult to solve. The dust grains are assumed to be spherical particles with a single size composed of astronomical silicates, so that the scattering and polarization properties can be calculated using Mie theory.

References and downloads

Publication Pinte et al. 2009 [ADS]
Web site http://ipag.osug.fr/~pintec/benchmark
Ski file pinte.ski

SKIRT results

The figure below, comparable to Figure 7 of Peest et al. 2017 (see also Polarization test cases), shows polarization results produced by SKIRT for a disk with an edge-on optical depth of τ=106, at the inclinations 69.5 (top half) and 87.1 (bottom half). On the left are the linear polarization degree maps produced by SKIRT. The dust grain size is the same as the wavelength (1 μm), creating the intricate patterns in the maps. On the right are cuts 1 to 6 through the maps along with results produced by some of the codes participating in the original benchmark.

Performing this benchmark

To perform this benchmark, download the ski file provided above (References and downloads). Then pass the (name of) the ski file to SKIRT as a single command line argument. At the end of the simulation run, SKIRT outputs data frames and SEDs including the elements of the Stokes vector carring the polarization state. This information can be compared to the original benchmark results.