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The 6-GHz multibeam maser survey - II. Statistical analysis and galactic distribution of 6668-MHz methanol masers


Green, JA and Breen, SL and Fuller, GA and McClure-Griffiths, NM and Ellingsen, SP and Voronkov, MA and Avison, A and Brooks, K and Burton, MG and Chrysostomou, A and Cox, J and Diamond, PJ and Gray, MD and Hoare, MG and Masheder, MRW and Pestalozzi, M and Phillips, C and Quinn, LQ and Richards, AMS and Thompson, MA and Walsh, AJ and Ward-Thompson, D and Wong-McSweeney, D and Yates, JA, The 6-GHz multibeam maser survey - II. Statistical analysis and galactic distribution of 6668-MHz methanol masers, Monthly Notices of the Royal Astronomical Society, 469, (2) pp. 1383-1402. ISSN 0035-8711 (2017) [Refereed Article]


Copyright Statement

Copyright 2017 The authors. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society 2017 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

DOI: doi:10.1093/mnras/stx887


The Methanol Multibeam survey has produced the largest and most complete census of methanol and excited-state hydroxyl masers in the Galaxy to date. Observing the entire Galactic plane visible from the Southern hemisphere for 6668-MHz methanol and 6030/6035-MHz hydroxyl masers, to an rms sensitivity of 0.015Jykms−1, the survey has detected a total of 972 methanol maser sources, implying a total Galactic population of ∼1290 sources with flux densities above the survey 3σ peak flux density limit of 0.51Jy. We present here the statistical properties of the methanol detections of the survey, including distributions in flux density, variability and range of source velocities. The data suggest that the weaker masers exhibit greater variability. We also present an analysis of the Galactic distribution of 6668-MHz methanol masers. For the Galactic distribution, we present kinematic distance resolutions to an additional 202 sources to those published previously, and collate these with previous allocations, as well as exploring a recent Bayesian distance approach based on maser parallaxes to separately determine distances. We examine Galactic structure and determine the luminosity function of the Galactic population of methanol masers. We find that more luminous masers have an evenly distributed wide range of velocity widths compared with less luminous masers being dominated by narrow velocity ranges, with the implication that this may be tied to the evolution of the host protostar(s). We also see an indication that brighter sources are seen towards the arm origins.

Item Details

Item Type:Refereed Article
Keywords:masers, surveys, stars: formation, stars: massive, galaxy: structure
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:116960
Year Published:2017
Web of Science® Times Cited:35
Deposited By:Mathematics and Physics
Deposited On:2017-05-26
Last Modified:2018-04-27
Downloads:132 View Download Statistics

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