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New class I methanol masers
conference contribution
posted on 2023-05-23, 17:37 authored by Voronkov, MA, Caswell, JL, Simon EllingsenSimon Ellingsen, Breen, SL, Britton, TR, Green, JA, Sobolev, AM, Walsh, AJWe 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.
History
Publication title
Proceedings of the International Astronomical Union Symposium S287Editors
RS Booth, EML Humphreys & WHT VlemmingsPagination
433-440ISBN
978-1-10703-284-2Department/School
School of Natural SciencesPublisher
Cambridge University PressPlace of publication
United KingdomEvent title
International Astronomical Union Symposium S287Event Venue
Stellenbosch, South AfricaDate of Event (Start Date)
2012-01-29Repository Status
- Restricted