2006/10/05 by D. P. Stark, W. M. Goss, E. Churchwell +2 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Context (archaeology) #Field (mathematics) #Magnetic field #Maser #Star formation #Stellar, planetary, and galactic studies #Zeeman effect #astro-ph
paper · pdf · doi:10.1086/509863
published as Astrophys.J.656:943-951,2007 · 32 pages, 12 figures, accepted for publication in ApJ
arxiv created 2006/10/05 · openalex publication_date 2007/02/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present VLBA observations of 1667 MHz OH maser emission from the massive star formation region G5.89-0.39. The observations were phase-referenced, allowing the absolute positions of the masers to be obtained. The 1667 MHz masers have radial velocities that span ~50 km s -1 but show little evidence of tracing the bipolar molecular outflow, as has been claimed in previous studies. We identify 23 Zeeman pairs through comparison of masers in left and right circular polarization. Magnetic field strengths range from -2 to +2 mG, and an ordered reversal in magnetic field direction is observed toward the southern region of the UC H II region. We suggest that the velocity and magnetic field structure of the 1667 MHz masers can be explained in the context of a model in which the masers arise in a neutral shell just outside a rapidly expanding ionized shell.