VLBA observations of G5.89-0.39: OH masers and magnetic field structure

D. P. Stark, W. M. Goss, E. Churchwell, V. L. Fish, I. M. Hoffman

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)943-951
Number of pages9
JournalAstrophysical Journal
Volume656
Issue number2 I
DOIs
StatePublished - Feb 20 2007

Keywords

  • H II regions
  • ISM: individual (G5.89-0.39)
  • ISM: magnetic fields
  • Masers
  • Stars: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Stark, D. P., Goss, W. M., Churchwell, E., Fish, V. L., & Hoffman, I. M. (2007). VLBA observations of G5.89-0.39: OH masers and magnetic field structure. Astrophysical Journal, 656(2 I), 943-951. https://doi.org/10.1086/509863