Discovery of the Zeeman Effect in the 44 GHz Class I methanol maser line

Abstract

We report the discovery of the Zeeman effect in the 44 GHz Class I methanol maser line. The observations were carried out with 22 antennas of the EVLA toward a star forming region in OMC-2. Based on our adopted Zeeman splitting factor of z = 1.0 Hz/mG, we detect a line of sight magnetic field of 18.4 +/- 1.1 mG toward this source. Since such 44 GHz methanol masers arise from shocks in the outflows of star forming regions, we can relate our measurement of the post-shock magnetic field to field strengths indicated by species tracing pre-shock regions, and thus characterize the large scale magnetic field. Moreover, since Class I masers trace regions more remote from the star forming core than Class II masers, and possibly earlier phases, magnetic fields detected in 6.7 GHz Class II and 36 GHz and 44 GHz Class I methanol maser lines together offer the potential of providing a more complete picture of the magnetic field. This motivates further observations at high angular resolution to find the positional relationships between Class I and Class II masers, and masers at various frequencies within each category. In particular, methanol masers are widespread in high- as well as intermediate-mass star forming regions, and our discovery provides a new method of studying the magnetic field in such regions, by observing small physical scales that are not accessible by any other lines.

Accepted to ApJ (Letters), 2 figures

References in corpus (5)

• Theory of Star Formation
• Full-Polarization Observations of OH Masers in Massive Star-Forming Regions: II. Maser Properties and the Interpretation of Polarization
• Millimeter- and Submillimeter-Wave Observations of the OMC-2/3 Region. III. An Extensive Survey for Molecular Outflows
• A new probe of magnetic fields during high-mass star formation: Zeeman splitting of 6.7 GHz methanol masers
• Conference Summary: The Cosmic Agitator - Magnetic Fields in the Galaxy

Cited by in corpus (10)

• Physical characteristics of bright Class I methanol masers
• Review of Zeeman Effect Observations of Regions of Star Formation
• Characterization of methanol as a magnetic field tracer in star-forming regions
• A 95 GHz Class I Methanol Maser Survey Toward A Sample of GLIMPSE Point Sources Associated with BGPS Clumps
• A search for 95 GHz class I methanol masers in molecular outflows
• Z45: A New 45-GHz Band Dual-Polarization HEMT Receiver for the NRO 45-m Radio Telescope
• Linear Polarization of Class I Methanol Masers in Massive Star-Forming Regions
• First clear detection of the CCS Zeeman splitting toward the pre-stellar core, Taurus Molecular Cloud-1
• Comparison of Two Epochs of the Zeeman Effect in the 44 GHz Class I methanol (CH3OH) maser line in OMC-2
• Very Large Array Detection of the 36 GHz Zeeman Effect in DR21W Revisited