Publications by Patrick Roche

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

Monthly Notices of the Royal Astronomical Society 327 (2001) 233-243

T Fujiyoshi, CH Smith, CM Wright, TJT Moore, DK Aitken, PF Roche

We present 8-13 μm spectropolarimetry, and 12- and 2-μm 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 ∼200 K and the optical depth of the absorbing dust at 9.7 μm is ∼ 1.5. Fits are also made to the polarimetry spectra, which show a reasonably constant peak absorptive polarization (∼3.4 per cent at 43°) across the face of the H II region. This absorptive polarization position angle is consistent with that found by the 2-μm imaging polarimetry (38° ± 6°) 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-μm polarization image, the emissive polarization pattern that is intrinsic to the star-forming region is revealed. A probable magnetic field co nfiguration implied by the intrinsic polarization suggests star formation initially influenced by the Galactic magnetic field which is eventually perturbed by the star formation process.

Show full publication list