We have used the ATNF Mopra antenna and the SEST antenna to search in the directions of several class II methanol maser sources for emission from six methanol transitions in the frequency range 85-115 GHz. The transitions were selected from excitation studies as potential maser candidates. Methanol emission at one or more frequencies was detected from five of the maser sources, as well as from Orion KL. Although the lines are weak, we find evidence of maser origin for three new lines in G345.01 + 1.79, and possibly one new line in G9.62+0.20. The observations, together with published maser observations at other frequencies, are compared with methanol maser modelling for G345.01 + 1.79 and NGC 6334F. We find that the majority of observations in both sources are consistent with a warm dust (175K) pumping model at hydrogen density ∼106cm-3 and methanol column density ∼5 × 1017 cm-2. The substantial differences between the maser spectra in the two sources can be attributed to the geometry of the maser region.

Item Type:	Refereed Article
Research Division:	Physical Sciences
Research Group:	Astronomical and Space Sciences
Research Field:	Galactic Astronomy
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Physical Sciences
Author:	Ellingsen, SP (Professor Simon Ellingsen)
Author:	Dodson, R (Mr Richard Dodson)
ID Code:	22068
Year Published:	2001
Web of Science® Times Cited:	39
Deposited By:	Physics
Deposited On:	2001-08-01
Last Modified:	2002-05-09
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