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New class I methanol masers


Voronkov, MA and Caswell, JL and Ellingsen, SP and Breen, SL and Britton, TR and Green, JA and Sobolev, AM and Walsh, AJ, New class I methanol masers, Proceedings of the International Astronomical Union Symposium S287, 29 January − 3 February 2012, Stellenbosch, South Africa, pp. 433-440. ISBN 978-1-10703-284-2 (2012) [Non Refereed Conference Paper]

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DOI: doi:10.1017/S174392131200748X


We review properties of all known collisionally pumped (class I) methanol maser series based on observations with the Australia Telescope Compact Array (ATCA) and the Mopra radio telescope. Masers at 36, 84, 44 and 95 GHz are most widespread, while 9.9, 25, 23.4 and 104 GHz masers are much rarer, tracing the most energetic shocks. A survey of many southern masers at 36 and 44 GHz suggests that these two transitions are highly complementary. The 23.4 GHz maser is a new type of rare class I methanol maser, detected only in two high-mass star-forming regions, G357.97-0.16 and G343.12-0.06, and showing a behaviour similar to 9.9, 25 and 104 GHz masers. Interferometric positions suggest that shocks responsible for class I masers could arise from a range of phenomena, not merely an outflow scenario. For example, some masers might be caused by interaction of an expanding Hii region with its surrounding molecular cloud. This has implications for evolutionary sequences incorporating class I methanol masers if they appear more than once during the evolution of the star-forming region. We also make predictions for candidate maser transitions in the ALMA frequency range.

Item Details

Item Type:Non Refereed Conference Paper
Keywords:methanol, masers, molecules, jets and outflows
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)
ID Code:85110
Year Published:2012
Deposited By:Mathematics and Physics
Deposited On:2013-06-14
Last Modified:2013-12-06

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