12.2-GHz methanol maser MMB follow-up catalogue – IV. Longitude range 20°–60

• Published in: Monthly notices of the Royal Astronomical Society 2016-07, Vol.459 (4), p.4066-4087
• Main Authors: Breen, S. L., Ellingsen, S. P., Caswell, J. L., Green, J. A., Voronkov, M. A., Avison, A., Fuller, G. A., Quinn, L. J.
• Format: Article
• Language: English
• Subjects: Astronomy; Methanol; Stars & galaxies; Velocity
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stw965

This is the fourth and final instalment of a series of catalogues presenting 12.2-GHz methanol maser observations made towards each of the 6.7-GHz methanol masers detected in the Methanol Multibeam (MMB) survey. This final portion of the survey covers the 20°–60° longitude range, increasing the 12.2-GHz follow-up range to the full MMB coverage of 186° ≥ l ≤ 60° and |b| ≤ 2°. Towards a total of 260 6.7-GHz MMB methanol masers (we were unable to observe five of the MMB sources in this longitude range) we detect 116 12.2-GHz masers counterparts, 64 of which were discovered in this survey. Including data from the literature, we find that there are 12.2-GHz methanol masers towards 47.1 per cent of the 6.7-GHz methanol masers in this portion of the Galaxy. Across the entire MMB survey range, we find a detection rate of 45.3 per cent. We find that the detection rate of 12.2-GHz methanol masers as a function of Galactic longitude is not uniform and there is an excess of masers with broad velocity ranges at longitudes near 30° and 330°. Comparing the occurrence of 12.2-GHz methanol masers with MMB-targeted CO observations has shown that those outflows associated with a 12.2-GHz source have a larger average dynamical time-scale than those associated with only 6.7-GHz methanol masers, supporting the notion that the 12.2-GHz masers are associated with a later phase of high-mass star formation.