Prof Patrick Roche

Abstract:

We present near-infrared broad-band JHK' images of the southern massive star-forming region G333.6-0.2. The slope of the K-luminosity function towards the region (0.24 ± 0.01) is considered to be equivalent to that expected for main-sequence stars in the solar neighbourhood. Point sources with their (H - K) colour greater than 1 are more likely to be located in extended emission and it is suggested that these objects are physically associated with the H II region.

Abstract:

Linear polarimetry in the mid-infrared can be used to obtain magnetic field directions in astronomical sources. However, since the polarization can arise from emission and/or absorption from aligned grains, care is needed to plan observations so that enough information is obtained to identify and separate the components of polarization. Procedures for doing this from spectropolarimetry, and from polarimetric imaging at a minimum of two wavebands and making an appropriate filter choice, are presented here, together with an example.