SPLASH: the Southern Parkes Large-Area Survey in Hydroxyl – first science from the pilot region
MetadataShow full item record
The Southern Parkes Large-Area Survey in Hydroxyl (SPLASH) is a sensitive, unbiased, and fully sampled survey of the southern Galactic plane and Galactic Centre in all four ground-state transitions of the hydroxyl (OH) radical. The survey provides a deep census of 1612-, 1665-, 1667-, and 1720-MHz OH absorption and emission from the Galactic interstellar medium, and is also an unbiased search for maser sources in these transitions. We present here first results from the SPLASH pilot region, which covers Galactic longitudes 334° to 344° and latitudes ±2?. Diffuse OH is widely detected in all four transitions, with optical depths that are always small (averaged over the Parkes beam), and with departures from local thermodynamic equilibrium common even in the 1665- and 1667-MHz main lines. To a 3σ sensitivity of ~30 mK, we find no evidence of OH envelopes extending beyond the CO-bright regions of molecular cloud complexes, and conclude that the similarity of the OH excitation temperature and the level of the continuum background is at least partly responsible for this. We detect masers and maser candidates in all four transitions, approximately 50 per cent of which are new detections. This implies that SPLASH will produce a substantial increase in the known population of ground-state OH masers in the southern Galactic plane.
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2014 The Authors, Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Showing items related by title, author, creator and subject.
Qiao, H.; Walsh, Andrew; Green, J.; Breen, S.; Dawson, J.; Ellingsen, S.; Gómez, J.; Jordan, Christopher; Shen, Z.; Lowe, V.; Jones, P. (2016)We report on high spatial resolution observations, using the Australia Telescope Compact Array (ATCA), of ground-state OH masers. These observations were carried out toward 196 pointing centers previously identified in ...
Voronkov, M.; Walsh, Andrew; Caswell, J.; Ellingsen, S.; Breen, S.; Longmore, S.; Purcell, C.; Urquhart, J. (2011)We report the first detection of a methanol maser in the 101–92 A- transition at 23.4 GHz, discovered during the H2O southern Galactic Plane Survey (HOPS) with the 22-m Mopra Radio Telescope. In the region covered by ...
Walsh, Andrew; Breen, S.; Britton, T.; Brooks, K.; Burton, M.; Cunningham, M.; Green, J.; Harvey-Smith, L.; Hindson, L.; Hoare, M.; Indermuehle, B.; Jones, P.; Lo, N.; Longmore, S.; Lowe, V.; Phillips, C.; Purcell, C.; Thompson, M.; Urquhart, J.; Voronkov, M.; White, G.; Whiting, M. (2011)We present first results of the H2O Southern Galactic Plane Survey (HOPS), using the Mopra Radio Telescope with a broad-band backend and a beam size of about 2 arcmin. We have observed 100 deg2 of the southern Galactic ...