A Survey for Hydroxyl in the THOR Pilot Region around W43

Abstract

We report on observations of the hydroxyl radical (OH) within The H{\sc I}, OH Recombination line survey (THOR) pilot region. The region is bounded approximately between Galactic coordinates l=29.2 to 31.5${}^{\circ }$ and b=-1.0 to +1.0${}^{\circ }$ 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.

accepted for publication in MNRAS

References in corpus (13)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• Theory of Star Formation
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• The VLA Galactic Plane Survey
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• The 6-GHz Multibeam Maser Survey I. Techniques
• The Southern Galactic Plane Survey: Polarized Radio Continuum Observations and Analysis
• ATLASGAL --- Complete compact source catalogue: 280\degr\ $<\ell <$ 60\degr
• A SCUBA imaging survey of ultracompact HII regions: The environments of massive star formation
• Accurate water maser positions from HOPS
• H2O Maser Observations of Candidate Post-AGB Stars and Discovery of Three High-velocity Water Sources
• THOR - The HI, OH, Recombination Line Survey of the Milky Way - The pilot study: HI observations of the giant molecular cloud W43
• Search for radiative pumping lines of OH masers: I. The 34.6um absorption line towards 1612 MHz OH maser sources

Cited by in corpus (14)

• High-Mass Star and Massive Cluster Formation in the Milky Way
• The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview
• Probing the "Sea" of Galactic Cosmic Rays with Fermi-LAT
• The HI/OH/Recombination line survey of the inner Milky Way (THOR)
• Continuum sources from the THOR survey between 1 and 2 GHz
• The scaling relations and star formation laws of ministarburst complexes
• OH maser emission in the THOR survey of the northern Milky Way
• Inferring the composition of super-Jupiter mass companions of pulsars with radio line spectroscopy
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). VI. Dense gas and mini-starbursts in the W43 giant molecular cloud complex
• OH absorption in the first quadrant of the Milky Way as seen by THOR
• Polarization properties of OH emission in planetary nebulae
• ATLASGAL -- Relationship between dense star forming clumps and interstellar masers
• The hydroxyl satellite-line `flip' as a tracer of expanding HII regions
• OH in the diffuse interstellar medium: physical modelling and prospects with upcoming SKA precursor/pathfinder surveys