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Detection of 36GHz Class I Methanol Maser Emission toward NGC 4945

Citation

McCarthy, TP and Ellingsen, SP and Chen, X and Breen, SL and Voronkov, MA and Qiao, H-h, Detection of 36GHz Class I Methanol Maser Emission toward NGC 4945, Astrophysical Journal, 846, (2) Article 156. ISSN 0004-637X (2017) [Refereed Article]


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Copyright Statement

Copyright 2017 The American Astronomical Society

DOI: doi:10.3847/1538-4357/aa872c

Abstract

We have searched for emission from the 36.2 GHz (${4}_{-1}\to {3}_{0}{\rm{E}}$) methanol transition toward NGC 4945, using the Australia Telescope Compact Array. 36.2 GHz methanol emission was detected offset southeast from the Galactic nucleus. The methanol emission is narrow, with a line width <10 km s−1 and a luminosity five orders of magnitude higher than Galactic class I masers from the same transition. These characteristics combined the with physical separation from the strong central thermal emission suggests that the methanol emission is a maser. This emission is a factor of ~90 more luminous than the widespread emission detected from the Milky Way central molecular zone. This is the fourth detection of extragalactic class I emission and the third detection of extragalactic 36.2 GHz maser emission. These extragalactic class I methanol masers do not appear to be simply highly luminous variants of Galactic class I emission and instead appear to trace large-scale regions of low-velocity shocks in molecular gas, which may precede, or be associated with, the early stages of large-scale star formation.

Item Details

Item Type:Refereed Article
Keywords:masers, galaxies: individual (NGC 4945), galaxies: starburst, radio lines: ISM
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Cosmology and Extragalactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:McCarthy, TP (Mr Tiege McCarthy)
Author:Ellingsen, SP (Professor Simon Ellingsen)
ID Code:121201
Year Published:2017
Deposited By:Mathematics and Physics
Deposited On:2017-09-15
Last Modified:2017-11-13
Downloads:0

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