Radiative transfer simulations that describe the propagation of light from and through astronomical objects are gaining more and more importance when interpreting observational data. One observational signature that has not been fully exploited is polarization, which is mainly due to scattering off electrons and dust grains. Recently, this potential is being realized, and a growing number of radiative transfer codes are capable of calculating and predicting polarimetry from astronomical objects.
We have developed an elegant reference-frame-free description of scattering polarization and implemented it into the Monte Carlo radiative transfer code SKIRT. We have validated the accuracy of our implementation using simple test cases and a detailed comparison to other codes. Using our new implementation, we simulate imaging and polarization maps of a realistic spiral galaxy model, with the aim to investigate the possibility to use polarimetry to detect spiral arms in edge-on galaxies. We find that we can easily identify the signatures of spiral structure using polarization information at 1 micron, complementing the information obtainable from regular imaging data.