A survey for hydroxyl in the THOR pilot region around W43

Walsh, A. and Beuther, H. and Bihr, S. and Johnston, K. and Dawson, J. and Ott, J. and Longmore, S. et al. 2015. A survey for hydroxyl in the THOR pilot region around W43. Monthly Notices of the Royal Astronomical Society. 455 (3): pp. 3494-3510.

Source Title

Monthly Notices of the Royal Astronomical Society

DOI

10.1093/mnras/stv2446

ISSN

0035-8711

School

Curtin Institute of Radio Astronomy (Physics)

Remarks

This article has been accepted for publication in Monthly Notices of The Royal Astronomical Society, © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

URI

http://hdl.handle.net/20.500.11937/45920

Collection

Curtin Research Publications

Abstract

We report on observations of the hydroxyl radical (OH) within The Hι, OH, Recombination line survey (THOR) pilot region. The region is bounded approximately between Galactic coordinates l = 29 .2 to 31 .5 and b = −1 .0 to +1 .0 and includes the high-mass star-forming region W43. We identify 103 maser sites, including 72 with 1612 MHz masers, 42 showing masers in either of the main-line transitions at 1665 and 1667 MHz and four showing 1720 MHz masers. Most maser sites with either main-line or 1720 MHz emission are associated with star formation, whereas most of the 1612 MHz masers are associated with evolved stars. We find that nearly all of the main-line maser sites are co-spatial with an infrared source, detected by GLIMPSE. We also find diffuse OH emission, as well as OH in absorption towards selected unresolved or partially resolved sites. Extended OH absorption is found towards the well-known star-forming complex W43 Main.