Submillimetre polarization and constraints on dust grain alignment

Polarization at 800 and 1100um has been observed in the star-forming regions Mon R2, DR21 and W3-IRS4. These data have been used to test proposed mechanisms for producing polarized dust emission in the submillimetre. It was found that illumination effects are not sufficient to explain the observed polarization, and that some degree of grain alignment is required. In general, mechanical alignment (via collisions with molecules) and radiative alignment of asymmetrical grains are the most probable mechanisms.