Open AccessCo‐propagation of maser emission at 1720 and 4765 MHz
Author(s) -
Gray M. D.,
Cohen R. J.,
Richards A. M. S.,
Yates J. A.,
Field D.
Publication year - 2001
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 - 10.1046/j.1365-8711.2001.04349.x
Subject(s) - maser , physics , zeeman effect , astrophysics , merlin (protein) , allowance (engineering) , astronomy , magnetic field , medicine , mechanical engineering , quantum mechanics , cancer , engineering , suppressor
MERLIN observations are presented of OH 4765‐MHz and OH 1720‐MHz masers in the massive star‐forming region W3(OH). Two of the three intense spots of maser emission at 4765 MHz are spatially coincident with two similar spots at 1720 MHz in both left‐hand circular (LHC) and right‐hand circular (RHC) polarizations, to an accuracy of 15 mas. The spots also overlap in velocity when allowance is made for Zeeman splitting of the 1720‐MHz line. We conclude that we have found two examples of masers in different rotational levels of OH which are co‐propagating through the same column of gas and experiencing competitive gain effects. The third 4765‐MHz maser spot was found to have no overlapping counterpart amongst the 1720‐MHz masers.