Infrared polarimetry of the southern massive star-forming region G333.6-0.2

We present 8-13 mum spectropolarimetry, and 12- and 2-mum imaging polarimetry of the southern massive star-forming region G333.6-0.2. Spectropolarimetry measurements show that the polarization observed towards the nebula contains a mixture of both absorptive and emissive polarizations. Model fitting to the spectra indicates that the temperature of the mid-infrared emitting dust grains is generally similar to 200 K and the optical depth of the absorbing dust at 9.7 mum is similar to1.5. Fits are also made to the polarimetry spectra, which show a reasonably constant peak absorptive polarization (similar to3.4 per cent at 43 degrees) across the face of the H II region. This absorptive polarization position angle is consistent with that found by the 2-mum imaging polarimetry (38 degrees +/- 6 degrees) and is most likely due to the Galactic magnetic field local to G333.6-0.2. When the absorptive polarization is subtracted from the 12-mum polarization image, the emissive polarization pattern that is intrinsic to the star-forming region is revealed. A probable magnetic field configuration implied by the intrinsic polarization suggests star formation initially influenced by the Galactic magnetic field which is eventually perturbed by the star formation process.