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Discovery of new 19.9-GHz methanol masers in star-forming regions


Ellingsen, SP and Cragg, DM and Lovell, JEJ and Sobolev, AM and Ramsdale, PD and Godfrey, PD, Discovery of new 19.9-GHz methanol masers in star-forming regions, Monthly Notices of the Royal Astronomical Society, 354, (2) pp. 401-413. ISSN 0035-8711 (2004) [Refereed Article]

DOI: doi:10.1111/j.1365-2966.2004.08200.x


We have used the NASA Tidbinbilla 70-m antenna to search for emission from the 21-30 E (19.9-GHz) transition of methanol. The search was targeted towards 22 star formation regions that exhibit maser emission in the 107.0-GHz 31-40 A+ methanol transition, and in the 6.6-GHz 51-60 A+ transition characteristic of class II methanol maser sources. A total of seven sources were detected in the 21-30 E transition, six of these being new detections. Many of the new detections are weak (≳0.5 Jy), however, they appear to be weak masers rather than thermal or quasi-thermal emission. We find a strong correlation between sources that exhibit 19.9-GHz methanol masers and those that both have the class II methanol masers projected against radio continuum emission and have associated 6035-MHz OH masers. This suggests that the 19.9-GHz methanol masers arise in very specific physical conditions, probably associated with a particular evolutionary phase. In the model of Cragg, Sobolev & Godfrey these observations are consistent with gas temperatures of 50 K, dust temperatures of 150-200 K and gas densities of 106.5-107.5 cm-3.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
UTAS Author:Lovell, JEJ (Dr Jim Lovell)
UTAS Author:Ramsdale, PD (Mr Patrick Ramsdale)
ID Code:30740
Year Published:2004
Web of Science® Times Cited:22
Deposited By:Physics
Deposited On:2004-08-01
Last Modified:2007-08-29

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