Discovery of the Zeeman Effect in the 36 and 44 GHz Class I Methanol Maser Lines with the EVLA

Abstract

We report the discovery of the Zeeman effect in the 36 GHz and the 44 GHz Class I methanol maser lines. The observations were carried out with the Expanded Very Large Array (EVLA) toward the star-forming regions M8E (at 36 GHz) and OMC-2 (at 44 GHz). The detected line of sight magnetic field values are −31.3 ± 3.5 mG and 20.2 ± 3.5 mG to the northwest and southeast of the maser line peak in M8E, respectively, and 18.4 ± 1.1 mG toward the peak of the maser line in OMC-2. The detected fields are comparable and are not s ignificantly different from those measured in the 6.7 GHz Class II methanol maser line toward other star forming regions. This indicates that methanol masers may trace the large scale magnetic field, or that the magnetic field remains unchanged during the early evolution of star forming regions.