Open AccessThe association of OH and methanol masers in W3(OH)
Author(s) -
Etoka S.,
Cohen R. J.,
Gray M. D.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09130.x
Subject(s) - maser , physics , zeeman effect , excited state , astrophysics , methanol , magnetic field , atomic physics , astronomy , chemistry , organic chemistry , quantum mechanics
We present single‐baseline Multi‐Element Radio‐Linked Interferometer Network (MERLIN) measurements of excited OH 6.0‐GHz masers and methanol 6.7‐GHz masers for the source W3(OH). These allow us to compare the positions of individual maser spots of these two species to ∼15 mas accuracy for the first time, and to compare these with previously published positions of ground‐state OH masers near 1.7 GHz and excited‐state OH masers near 4.7 GHz. There is a strong association between OH 6035‐MHz and 1665‐MHz masers. OH and methanol have very similar distributions, but associations of individual masers are relatively rare: most methanol 6.7‐GHz masers are within 100 mas of OH 6.0‐GHz masers, but only four methanol masers are within 15 mas of an OH 6.0‐GHz maser. There are no correspondences of either species with excited OH 4.7‐GHz masers. Zeeman splitting of the 6.0‐GHz OH lines indicates an ordered magnetic field ranging from 3.2 to 14.4 mG. The magnetic fields estimated from co‐propagating masers such as 6035 and 1665 MHz are generally in good agreement with each other.