Precise Positions of Methanol Masers
  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 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.
