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Accurate water maser positions from HOPS

Walsh, AJ and Purcell, CR and Longmore, SN and Breen, SL and Green, JA and Harvey-Smith, L and Jordan, CH and Macpherson, C (2014) Accurate water maser positions from HOPS. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 442 (3). pp. 2240-2252. ISSN 0035-8711

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Abstract

We report on high spatial resolution water maser observations, using the Australia Telescope Compact Array, towards water maser sites previously identified in the H2O southern Galactic Plane Survey (HOPS). Of the 540 masers identified in the single-dish observations of Walsh et al. (2011), we detect emission in all but 31 fields. We report on 2790 spectral features (maser spots), with brightnesses ranging from 0.06 Jy to 576 Jy and with velocities ranging from −238.5 to +300.5 kms−1. These spectral features are grouped into 631 maser sites. We have compared the positions of these sites to the literature to associate the sites with astrophysical objects. We identify 433 (69 per cent) with star formation, 121 (19 per cent) with evolved stars and 77 (12 per cent) as unknown. We find that maser sites associated with evolved stars tend to have more maser spots and have smaller angular sizes than those associated with star formation. We present evidence that maser sites associated with evolved stars show an increased likelihood of having a velocity range between 15 and 35 kms−1 compared to other maser sites. Of the 31 non-detections, we conclude they were not detected due to intrinsic variability and confirm previous results showing that such variable masers
tend to be weaker and have simpler spectra with fewer peaks.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record "Accurate water maser positions from HOPS" is available online at http://dx.doi.org/10.1093/mnras/stu989
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: OXFORD UNIV PRESS
Related URLs:
Date Deposited: 08 Jun 2016 10:40
Last Modified: 08 Jun 2016 10:40
DOI or Identification number: 10.1093/mnras/stu989
URI: http://researchonline.ljmu.ac.uk/id/eprint/3723

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