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

Abstract

We have searched for emission from the 36.2 GHz ($4_{-1}\to 3_0$E) methanol transition towards NGC 4945, using the Australia Telescope Compact Array. 36.2 GHz methanol emission was detected offset south-east from the Galactic nucleus. The methanol emission is narrow, with a linewidth <10 kms${}^{-1}$, 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 $\sim 90$ more luminous than the widespread emission detected from the Milky Way central molecular zone (CMZ). 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.

7 pages, 3 figures, 1 table

References in corpus (11)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC4945
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• Detection of 36 GHz class I methanol maser emission towards NGCS253
• Class I methanol masers in NGC253: Alcohol at the end of the bar
• Detection of a methanol megamaser in a major-merger galaxy
• Detection of 183 GHz water megamaser emission towards NGC 4945
• Submillimeter H${}_2$O megamasers in NGC 4945 and the Circinus galaxy
• Search for sub-millimeter H2O masers in active galaxies - the detection of a 321 GHz H2O maser in NGC4945
• Detection of HC${}_3$N maser emission in NGC253

Cited by in corpus (12)

• Online Database of Class I Methanol Masers
• Molecular line emission in NGC 4945, imaged with ALMA
• Methanol masers in NGC 253 with ALCHEMI
• Diagnostics of a Nuclear Starburst: Water and Methanol Masers
• 84-GHz methanol masers, their relationship to 36-GHz methanol masers and their molecular environments
• Astrophysical constraints on the proton-to-electron mass ratio with FAST
• 36 GHz methanol lines from nearby galaxies: maser or quasi-thermal emission?
• Investigations of the Class I methanol masers in NGC 4945
• Detection of 84-GHz class I methanol maser emission towards NGC 253
• Variability in extragalactic class I methanol masers: New maser components toward NGC4945 and NGC253
• Extragalactic maser surveys
• The Maser-Starburst connection in NGC253