Large Magnetic Fields and Motions of OH Masers in W75N
/ Abstract
We report on a second epoch of VLBA observations of the 1665 and 1667 MHz OH masers in the massive star-forming region W75N. We find evidence to confirm the existence of very strong (~40 mG) magnetic fields near source VLA 2. The masers near VLA 2 are dynamically distinct and include a very bright spot apparently moving at 50 km s-1 relative to those around VLA 1. This fast-moving spot may be an example of a rare class of OH masers seen in outflows in star-forming regions. Due to the variability of these masers and the rapidity of their motions, tracking these motions will require multiple observations over a significantly shorter time baseline than obtained here. Proper motions of the masers near VLA 1 are more suggestive of streaming along magnetized shocks rather than Keplerian rotation in a disk. The motions of the easternmost cluster of masers in W75N(B) may be tracing slow expansion around an unseen exciting source.
Journal: The Astrophysical Journal
DOI: 10.1086/510578