Strong magnetic field in W75N OH maser flare

Abstract

A flare of OH maser emission was discovered in W75N in 2000. Its location was determined with the VLBA to be within 110 au from one of the ultracompact H II regions, VLA2. The flare consisted of several maser spots. Four of the spots were found to form Zeeman pairs, all of them with a magnetic field strength of about 40 mG. This is the highest ever magnetic field strength found in OH masers, an order of magnitude higher than in typical OH masers. Three possible sources for the enhanced magnetic field are discussed: (i) the magnetic field of the exciting star dragged out by the stellar wind; (ii) the general interstellar field in the gas compressed by the MHD shock; and (iii) the magnetic field of planets which orbit the exciting star and produce maser emission in gaseous envelopes.

arXiv comment5 pages, 3 figures. to be published in MNRAS

References in corpus (6)

• Full-Polarization Observations of OH Masers in Massive Star-Forming Regions: I. Data
• The Magnetic Field in the Star-forming Region Cepheus A from Water Maser Polarization Observations
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• Large Magnetic Fields and Motions of OH Masers in W75 N
• An Arecibo Survey for Zeeman Splitting in OH Megamaser Galaxies
• Flares and Proper Motions of Ground-State OH Masers in W75N
• Monitoring of the polarized $H_{2}O$ maser emission around the massive protostars W75N(B)-VLA1 and W75N(B)-VLA2
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