MALT-45: a 7 mm survey of the southern Galaxy - I. Techniques and spectral line data
MetadataShow full item record
We present the first results from the MALT-45 (Millimetre Astronomer's Legacy Team-45 GHz) Galactic Plane survey. We have observed 5 square degrees (l = 330°–335°, b = ±0.°5) for spectral lines in the 7 mm band (42–44 and 48–49 GHz), including CS (1–0), class I CH3OH masers in the 7(0,7)–6(1,6) A+ transition and SiO (1–0) v = 0, 1, 2, 3. MALT-45 is the first unbiased, large-scale, sensitive spectral line survey in this frequency range. In this paper, we present data from the survey as well as a few intriguing results; rigorous analyses of these science cases are reserved for future publications. Across the survey region, we detected 77 class I CH3OH masers, of which 58 are new detections, along with many sites of thermal and maser SiO emission and thermal CS. We found that 35 class I CH3OH masers were associated with the published locations of class II CH3OH, H2O and OH masers but 42 have no known masers within 60 arcsec. We compared the MALT-45 CS with NH3 (1,1) to reveal regions of CS depletion and high opacity, as well as evolved star-forming regions with a high ratio of CS to NH3. All SiO masers are new detections, and appear to be associated with evolved stars from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). Generally, within SiO regions of multiple vibrational modes, the intensity decreases as v = 1, 2, 3, but there are a few exceptions where v = 2 is stronger than v = 1.
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.
Showing items related by title, author, creator and subject.
MALT-45: A 7mm survey of the southern Galaxy - II. ATCA follow-up observations of 44GHz class I methanol masersJordan, Christopher; Walsh, Andrew; Breen, S.; Ellingsen, S.; Voronkov, M.; Hyland, L. (2017)We detail interferometric observations of 44 GHz class I methanol masers detected by MALT-45 (a 7 mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 ...
Jordan, C.; Walsh, Andrew; Lowe, V.; Lo, N.; Purcell, C.; Voronkov, M.; Longmore, S. (2013)We introduce the Millimetre Astronomer’s Legacy Team – 45 GHz (MALT-45) Galactic plane survey and describe pilot survey results with the Australia Telescope Compact Array (ATCA).The pilot survey was conducted to test the ...
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 ...