Linear Polarization of Class I Methanol Masers in Massive Star-Forming Regions

Abstract

Class I methanol masers are found to be good tracers of the interaction between outflows from massive young stellar objects with their surrounding media. Although polarization observations of Class II methanol masers have been able to provide information about magnetic fields close to the central (proto)stars, polarization observations of Class I methanol masers are rare, especially at 44 and 95 GHz. We present the results of linear polarization observations of 39 Class I methanol maser sources at 44 and 95 GHz. These two lines are observed simultaneously with one of the 21 m Korean VLBI Network telescopes in single-dish mode. Approximately 60% of the observed sources have fractional polarizations of a few percent in at least one transition. This is the first reported detection of linear polarization of the 44 GHz methanol maser. The two maser transitions show similar polarization properties, indicating that they trace similar magnetic environments, although the fraction of the linear polarization is slightly higher at 95 GHz. We discuss the association between the directions of polarization angles and outflows. We also discuss some targets having different polarization properties at both lines, including DR21(OH) and G82.58+0.20, which show the 90° polarization angle flip at 44 GHz.

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Cited by in corpus (7)

• Review of Zeeman Effect Observations of Regions of Star Formation
• Online Database of Class I Methanol Masers
• Complex organic molecules detected in twelve high-mass star-forming regions with Atacama Large Millimeter/submillimeter Array (ALMA)
• 44 GHz methanol masers: Observations toward 95 GHz methanol masers
• Monitoring of the polarized $H_{2}O$ maser emission around the massive protostars W75N(B)-VLA1 and W75N(B)-VLA2
• Redshifted methanol absorption tracing infall motions of high-mass star formation regions
• The Zeeman Effect in the 44 GHz Class I Methanol (CH3OH) Maser Line Toward DR21W