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The evolutionary status of protostellar clumps hosting class II methanol masers


Jones, BM and Fuller, GA and Breen, SL and Avison, A and Green, JA and Traficante, A and Elia, DE and Ellingsen, SP and Voronkov, MA and Merello, M and Molinari, S and Schisano, E, The evolutionary status of protostellar clumps hosting class II methanol masers, Monthly Notices of the Royal Astronomical Society, 493, (2) pp. 2015-2041. ISSN 0035-8711 (2020) [Refereed Article]


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Copyright 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights Reserved

DOI: doi:10.1093/mnras/staa233


The Methanol MultiBeam survey (MMB) provides the most complete sample of Galactic massive young stellar objects (MYSOs) hosting 6.7 GHz class II methanol masers. We characterize the properties of these maser sources using dust emission detected by the Herschel Infrared Galactic Plane Survey (Hi-GAL) to assess their evolutionary state. Associating 731 (73 per cent) of MMB sources with compact emission at four Hi-GAL wavelengths, we derive clump properties and define the requirements of an MYSO to host a 6.7 GHz maser. The median far-infrared (FIR) mass and luminosity are 630 M and 2500 L for sources on the near side of Galactic centre and 3200 M and 10000 L for more distant sources. The median luminosity-to-mass ratio is similar for both at ∼4.2 L  M-1. We identify an apparent minimum 70 μm luminosity required to sustain a methanol maser of a given luminosity (with L70L6.70.6⁠). The maser host clumps have higher mass and higher FIR luminosities than the general Galactic population of protostellar MYSOs. Using principal component analysis, we find 896 protostellar clumps satisfy the requirements to host a methanol maser but lack a detection in the MMB. Finding a 70 μm flux density deficiency in these objects, we favour the scenario in which these objects are evolved beyond the age where a luminous 6.7 GHz maser can be sustained. Finally, segregation by association with secondary maser species identifies evolutionary differences within the population of 6.7GHz sources.

Item Details

Item Type:Refereed Article
Keywords:masers–stars: formation–stars: massive
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:138248
Year Published:2020
Funding Support:Australian Research Council (DP180101061)
Web of Science® Times Cited:8
Deposited By:Physics
Deposited On:2020-03-30
Last Modified:2021-01-27
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