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Accurate OH Maser Positions. II. The Galactic Center Region

Citation

Qiao, H-H and Walsh, AJ and Breen, SL and Gomez, JF and Dawson, JR and Imai, H and Ellingsen, SP and Green, JA and Shen, Z-Q, Accurate OH Maser Positions. II. The Galactic Center Region, Astrophysical Journal Supplement Series, 239, (1) Article 15. ISSN 0067-0049 (2018) [Refereed Article]


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Copyright Statement

Copyright 2018 The American Astronomical Society

DOI: doi:10.3847/1538-4365/aae580

Abstract

We present high spatial resolution observations of ground-state OH masers achieved using the Australia Telescope Compact Array (ATCA). These observations were conducted toward 171 pointing centers where OH maser candidates were identified previously in the Southern Parkes Large-Area Survey in Hydroxyl toward the Galactic center region between Galactic longitudes of 355 and 5 and Galactic latitudes of −2 and +2. We detect maser emission toward 162 target fields and suggest that six out of nine nondetections are due to intrinsic variability. Due to the superior spatial resolution of the follow-up ATCA observations, we have identified 356 OH maser sites in the 162 target fields with maser detections. Almost half (161 of 356) of these maser sites have been detected for the first time in these observations. After comparing the positions of these 356 maser sites to the literature, we find that 269 (76%) sites are associated with evolved stars (two of which are PNe), 31 (9%) are associated with star formation, and four are associated with supernova remnants; we were unable to determine the origin of the remaining 52 (15%) sites. Unlike the pilot region, the infrared colors of evolved star sites with symmetric maser profiles in the 1612 MHz transition do not show obvious differences compared with those of evolved star sites with asymmetric maser profiles.

Item Details

Item Type:Refereed Article
Keywords:catalogs; ISM: molecules; masers; radio lines: ISM; stars: AGB and post-AGB; stars: formation
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
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
ID Code:129587
Year Published:2018
Deposited By:Mathematics and Physics
Deposited On:2018-12-07
Last Modified:2019-03-04
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