The Australia Telescope Compact Array has been used to observe more than 200 1665‐MHz hydroxyl masers south of declination −16° and derive their positions with typical rms uncertainties of 0.4 arcsec. Many of the 1665‐MHz maser sites are found to have 1667‐MHz OH maser counterparts which are coincident, within the errors. The resulting position list presented here includes all well‐documented, previously reported 1665‐MHz masers close to the Galactic plane in the galactic longitude range 230° (through 360°) to 13°. Nearly 50 newly discovered masers are also listed, chiefly in the longitude range 312° to 356°, where the observations were conducted as an intensive survey of a continuous zone close to the Galactic plane. Many of the maser sites are discussed briefly so as to draw attention to those possessing properties that are unusual among this large sample. Most of the masers are of the variety found in star‐forming regions – at the sites of newly formed massive stars and their associated ultracompact H ii regions. The new, accurate, positions reveal coincidences of the OH masers with the continuum radio emission, with the infrared emission from dust that accompanies such regions, and with emission from other maser species such as methanol at 6668 MHz and water at 22 GHz. By‐products of the survey, also presented here, include measurements of at least 11 objects that are not associated with massive star‐forming regions. They comprise several OH/IR stars (detected at the 1667‐ or 1665‐MHz transition of OH, though commonly found to be most prominent at the 1612‐MHz transition) and several unusual masers that may pinpoint other varieties of late‐type stars or protoplanetary nebulae.

Abstract:The Australia Telescope Compact Array (ATCA) has been used to determine positions for many southern methanol maser sites, with accuracy better than 1 arcsec. The results are presented here as a catalogue of more than 350 distinct sites, some of them new discoveries, and many others with positional precision 10-times better than existing published values. Clusters of 2 or 3 sites are occasionally found to account for single previously listed sources. This in turn reveals that the velocity range for each individual site is sometimes smaller than that of the originally tabulated (blended) source. Only a handful of examples then remain with a velocity range of more than 16 km s −1 at a single compact (less than 2 arcsec) site. The precise methanol positions now allow apparent coincidences with OH masers to be confidently accepted or rejected; this has led to the important conclusion that, where a 1665-MHz OH maser lies in a massive star formation region, at more than 80 percent of the OH sites there is a precisely coincident methanol maser. The methanol precision achieved here will also allow clear comparisons with likely associated IR sources when the next generation of far-IR surveys produce precise positions.

We present the second portion of an unbiased survey of the Galactic plane for 6668‐MHz methanol masers. This section of the survey spans the longitude range 6° to 20°. We report the detection of 119 maser sources, of which 42 are new discoveries. The masers are tightly constrained to the Galactic plane, with only four outside a latitude range of ±1°. This longitude region includes the brightest known 6668‐MHz methanol maser, 9.621+0.196, as well as the two brightest newly discovered sources in the southern survey as a whole. We list all the sources associated with the 3‐kpc arms within ±15° longitude and consider further candidates beyond 15° longitude. We identify three new sources associated with the Galactic bar and comment on the density of masers in relation to the bar orientation.

We present the fifth portion of an unbiased survey of the Galactic plane, |b| ≤ 2• , for 6668-MHz methanol masers. This section of the survey completes the Galactic longitude range visible to the Parkes radio telescope, incorporating the longitude range 20• -60• . Within this section of the survey we find 265 methanol masers, 64 new to the survey, bringing the total number of methanol masers detected across the full longitude coverage (186• , through 0 • , to 60 • ) to 972 sources.