Outflows from Luminous Young Stellar Objects: An Infrared Polarimetric Study

e present Near Infrared imaging polarimetry of three regions of massive starformation, G$192.16 - 3.82$, Cepheus A, and W42. In W42 we have discovered anew bipolar nebula located at the far side of the HII region behind the visiblecluster of exciting stars. The axis of this new nebula is aligned with themagnetic field threading the entire cluster region. Polarization in the bipolaroutflow nebulosity associated with G192.16 is consistent with a singleilluminating source, too faint to be detected at $2 \micron$. Polarization inthe reflection nebulosity associated with Ceph A requires more than oneilluminating source, although HW2 is clearly dominant. In all three objects,the magnetic field in the outflow at distances greater than $\sim 0.2$ pc isradial. In G192.16 the magnetic field geometry closer than $\sim 0.2$ pc to theembedded star appears chaotic. For G192.16 the outflow is not aligned with thesurrounding magnetic field, which lies in the galactic plane. In Ceph A, theoutflow axis could be interpreted as being aligned with the galactic plane, butthe magnetic field threading the region is not. Only in the case of W42 is themagnetic field threading the HII region aligned with the mean field in thesurrounding galactic plane.Comment: 1 LaTeX file, 10 figure