Outflows from Luminous YSOs: An Infrared Polarimetric Study

Abstract

e present Near Infrared imaging polarimetry of three regions of massive star formation, G$192.16-3.82$, Cepheus A, and W42. In W42 we have discovered a new bipolar nebula located at the far side of the HII region behind the visible cluster of exciting stars. The axis of this new nebula is aligned with the magnetic field threading the entire cluster region. Polarization in the bipolar outflow nebulosity associated with G192.16 is consistent with a single illuminating source, too faint to be detected at $2 \micron$. Polarization in the reflection nebulosity associated with Ceph A requires more than one illuminating source, although HW2 is clearly dominant. In all three objects, the magnetic field in the outflow at distances greater than $\sim 0.2$ pc is radial. In G192.16 the magnetic field geometry closer than $\sim 0.2$ pc to the embedded star appears chaotic. For G192.16 the outflow is not aligned with the surrounding magnetic field, which lies in the galactic plane. In Ceph A, the outflow axis could be interpreted as being aligned with the galactic plane, but the magnetic field threading the region is not. Only in the case of W42 is the magnetic field threading the HII region aligned with the mean field in the surrounding galactic plane.

1 LaTeX file, 10 figures

References in corpus (2)

• Magnetic Fields via Polarimetry: Progress of Grain Alignment Theory
• The Magnetic Field Geometry in DR21

Cited by in corpus (10)

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• 1.3mm polarized emission in the circumstellar disk of a massive protostar
• The disk-outflow system around the rare young O-type protostar W42-MME
• Massive young stellar object W42-MME: The discovery of an infrared jet using VLT/NACO near-infrared images
• The Variable Reflection Nebula Cepheus A East
• Near-Infrared Polarization Images of The Orion Molecular Cloud 1 South Region
• Near-Infrared Polarimetry and H${}_2$ emission toward Massive Young Stars: Discovery of a Bipolar Outflow associated to S235 e2s3