DISCOVERY OF THE ZEEMAN EFFECT IN THE 44 GHz CLASS I METHANOL (CH{sub 3}OH) MASER LINE
- Physics Department, DePaul University, 2219 North Kenmore Avenue, Byrne Hall 211, Chicago, IL 60614 (United States)
- National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
We report the discovery of the Zeeman effect in the 44 GHz Class I methanol (CH{sub 3}OH) maser line. The observations were carried out with 22 antennas of the Expanded Very Large Array toward a star-forming region in OMC-2. Based on our adopted Zeeman splitting factor of z = 1.0 Hz mG{sup -1}, we detect a line-of-sight magnetic field of 18.4 {+-} 1.1 mG toward this source. Since such 44 GHz CH{sub 3}OH 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 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, CH{sub 3}OH 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.
- OSTI ID:
- 21560438
- Journal Information:
- Astrophysical Journal Letters, Vol. 730, Issue 1; Other Information: DOI: 10.1088/2041-8205/730/1/L5; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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