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MALT-45: a 7mm survey of the southern Galaxy II. ATCA follow-up observations of 44GHz class I methanol masers

Citation

Jordan, CH and Walsh, AJ and Breen, SL and Ellingsen, SP and Voronkov, MA and Hyland, LJ, MALT-45: a 7mm survey of the southern Galaxy - II. ATCA follow-up observations of 44GHz class I methanol masers, Royal Astronomical Society. Monthly Notices, 471, (4) pp. 3915-3954. ISSN 0035-8711 (2017) [Refereed Article]


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Copyright Statement

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

DOI: doi:10.1093/mnras/stx1776

Abstract

We detail interferometric observations of 44 GHz class I methanol masers detected by MALT-45 (a 7 mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 maser spots across 77 maser sites. Using high-resolution positions, we compare the class I CH3OH masers to other star formation maser species, including CS (10), SiO v=0 and the H53 α radio-recombination line. Comparison between the cross- and auto-correlated data has allowed us to also identify quasi-thermal emission in the 44 GHz class I methanol maser line. We find that the majority of class I methanol masers have small spatial and velocity ranges (<0.5 pc and <5 km s−1), and closely trace the systemic velocities of associated clouds. Using 870 μm dust continuum emission from the ATLASGAL survey, we determine clump masses associated with class I masers, and find that they are generally associated with clumps between 1000 and 3000 M. For each class I methanol maser site, we use the presence of OH masers and radio recombination lines to identify relatively evolved regions of high-mass star formation; we find that maser sites without these associations have lower luminosities and preferentially appear towards dark infrared regions.

Item Details

Item Type:Refereed Article
Keywords:masers, surveys, stars: formation, ISM: molecules, Galaxy: structure, radio lines: ISM
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Galactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Jordan, CH (Mr Christopher Jordan)
Author:Ellingsen, SP (Professor Simon Ellingsen)
Author:Voronkov, MA (Dr Maxim Voronkov)
Author:Hyland, LJ (Mr Lucas Hyland)
ID Code:120639
Year Published:2017
Deposited By:Mathematics and Physics
Deposited On:2017-08-29
Last Modified:2017-09-21
Downloads:5 View Download Statistics

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