Enhanced density and magnetic fields in interstellar OH masers

Abstract

Aims: We have observed the 6030 and 6035 MHz transitions of OH in high-mass star-forming regions to obtain magnetic field estimates in both maser emission and absorption. Methods: Observations were taken with the Effelsberg 100 m telescope. Results: Our observations are consistent with previous results, although we do detect a new 6030 MHz maser feature near -70 km/s in the vicinity of W3(OH). In absorption we obtain a possible estimate of -1.1 +/- 0.3 mG for the average line-of-sight component of the magnetic field in the absorbing OH gas in K3-50 and submilligauss upper limits for the line-of-sight field strength in DR 21 and W3. Conclusions: These results indicate that the magnetic field strength in the vicinity of OH masers is higher than that of the surrounding, non-masing material, which in turn suggests that the density of masing OH regions is higher than that of their surroundings.

19 pages including online material, accepted to A&A

References in corpus (1)

• Full-Polarization Observations of OH Masers in Massive Star-Forming Regions: II. Maser Properties and the Interpretation of Polarization

Cited by in corpus (5)

• Structure of W3(OH) from Very High Spectral Resolution Observations of 5 Centimeter OH Masers
• Proper Motions of OH Masers and Magnetic Fields in Massive Star-Forming Regions
• A MERLIN Study of 6 GHz Excited-state OH & 6.7 GHz Methanol Masers in ON1
• Effelsberg Observations of Excited-State (6.0 GHz) OH in Supernova Remnants and W3(OH)
• Observations of the 6 Centimeter Lines of OH in Evolved (OH/IR) Stars