VERY LARGE ARRAY DETECTION OF THE 36 GHz ZEEMAN EFFECT IN DR21W REVISITED

Abstract

We report on the observation of the 36 GHz methanol maser line in the star-forming region DR21W to accurately measure the Zeeman effect. The Zeeman signature reported by Fish et al. became suspicious after an instrumental effect was discovered in the early days of the commissioning of the Very Large Array Wide-band Digital Architecture correlator. We conclude that the previously reported magnetic field strength of 58 mG (1.7 Hz mG[superscript –1]/z) is instrumental in nature and thus incorrect. With the improved performance of the array, we now deduce a 3σ limit of –4.7 to +0.4 mG (1.7 Hz mG[superscript –1]/z) for the line-of-sight component of the magnetic field strength in DR21W.