The Discovery of the Zeeman Effect in 38 GHz Class II Methanol Masers

TL;DR

This study reports the first detection of the Zeeman effect in 38 GHz Class II methanol masers, providing direct measurements of magnetic fields in high-mass star-forming regions, which are crucial for understanding star formation dynamics.

Contribution

The paper presents the first Zeeman effect detection in 38 GHz Class II methanol masers, enabling direct magnetic field measurements in high-mass star-forming regions.

Findings

Zeeman detections in several Gaussian components with $zB_{los}$ from 8 to 46 Hz.

Estimated magnetic fields of 8-46 mG in star-forming regions.

Magnetic field strengths consistent with those in 6.7 GHz methanol masers.

Abstract

Magnetic fields likely play an important role in star formation, but the number of directly measured magnetic field strengths remains scarce. We observed the 38.3 and 38.5 GHz Class II methanol (CH$_3$OH) maser lines toward the high mass star forming region NGC 6334F for the Zeeman effect. The observed spectral profiles have two prominent velocity features which can be further decomposed through Gaussian component fitting. In several of these fitted Gaussian components we find significant Zeeman detections, with $zB_{\rm los}$ in the range from 8 to 46 Hz. If the Zeeman splitting factor $z$ for the 38 GHz transitions is of the order of $\sim$1 Hz mG$^{-1}$, similar to that for several other CH$_3$OH maser lines, then magnetic fields in the regions traced by these masers would be in the range of 8-46 mG. Such magnetic field values in high mass star forming regions agree with those detected in the better-known 6.7 GHz Class II CH$_3$OH maser line. Since Class II CH$_3$OH masers are radiatively pumped close to the protostar and likely occur in the accretion disk or the interface between the disk and outflow regions, such fields likely have significant impact on the dynamics of these disks.