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Ground-state OH masers are relatively common in the vicinity of
high-mass star formation (HMSF), the circumstellar envelopes of
evolved giant and supergiant stars, and the interaction regions of
supernova remnants (SNRs) and their surrounding molecular clouds.
Qiao et al. present high spatial resolution ATCA observations of
ground-state OH masers
identified in the Southern Parkes Large-Area Survey in Hydroxyl
(SPLASH).
Comparison between these 362 maser sites with information presented in
the literature allowed categorizations of 238 sites (66%) as evolved
star sites, 63 (17%) as star formation, 8 (2%) as supernova remnants
and 53 (15%) as unknown maser sites (15%).
Qiao et al. compared star formation OH maser sites in the SPLASH
survey region to 6.7 GHz methanol maser sites from the Parkes Methanol
Multi-Beam (MMB) survey and 22 GHz water maser sites from the Mopra
HOPS survey. For OH maser sites, the largest overlap is with methanol
maser sites, with 89/118 (75%) OH maser sites having associated
methanol emission. Additionally 55 OH maser sites (47%) show 22 GHz
water masers. Water masers also have the largest overlap with
methanol masers, with 101/207 (49%) water masers associated with
methanol maser sites. A total of 173/318 (54%) methanol maser sites
are not associated with either OH or water masers. It was found that
80/118 (68%) of OH masers are associated with water masers.
More details are given in
the paper
to be published in Monthly Notices of the Royal Astronomical Society.
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