University Of Tasmania
149022 - Class I methanol masers related to shocks induced by bar rotation in the nearby starburst galaxy Maffei 2.pdf (1 MB)

Class I methanol masers related to shocks induced by bar rotation in the nearby starburst galaxy Maffei 2

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journal contribution
posted on 2023-05-21, 06:03 authored by Chen, X, Yang, T, Simon EllingsenSimon Ellingsen, Tiege McCarthyTiege McCarthy, Ren, Z-Y
We report the detection of class I methanol maser at the 36.2 GHz transition toward the nearby starburst galaxy Maffei 2 with the Karl G. Jansky Very Large Array. Observations of the 36.2 GHz transition at two epochs separated by ∼4 yr show consistencies in both the spatial distribution and flux density of the methanol emission in this transition. Similar to the detections in other nearby starbursts the class I methanol masers sites are offset by a few hundred pc from the center of the galaxy and appear to be associated with the bar edges of Maffei 2. Narrow spectral features with line widths of a few km s−1 are detected, supporting the hypothesis that they are masing. Compared to other nearby galaxies with the detections in the 36.2 GHz methanol maser transition, the maser detected in Maffei 2 has about an order of magnitude higher isotropic luminosity, and thus represents the first confirmed detection of class I methanol megamasers. The spatial distribution of the 36.2 GHz maser spot clusters may trace the rotational gas flow of the galactic bar, providing direct evidence that the class I methanol maser is related to shocks induced by galactic bar rotation. A tentative detection in the 6.7 GHz class II methanol maser (at a 5σ level) is also reported. This is comparable in luminosity to some of the 6.7 GHz maser sources detected in Galactic star-forming regions. The 6.7 GHz methanol emission appears to be associated with star formation activity in a smaller volume, rather than related to the larger-scale galactic activities.


Publication title

The Astrophysical Journal



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School of Natural Sciences


Institute of Physics Publishing, Inc

Place of publication

United States

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Copyright 2022 The Author(s) Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

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  • Open

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Expanding knowledge in the physical sciences