MN

Massive newly formed stars are obscured by dust, and their clearest signature is often at radio frequencies from strong molecular maser emission. In some cases, both hydroxyl and methanol masers are present. Maser position measurements of both species are then especially useful for exploring the immediate surroundings of the new-born star. The present study used the Australia Telescope Compact Array to observe 6.035-GHz OR maser emission in 35 fields; 30 of these were also observed at the 6.668-GHz methanol transition. In many of the fields the masers were found to be grouped into several distinct maser sites, allowing a total of 62 sites to be studied. Relative positions at 6.035 and 6.668 GHz could be registered to an accuracy of 0.1 arcsec. 29 sites harbour both 6.035-GHz OR and 6.668-GHz methanol, and most of these have sufficient maser features to reveal that the distributions of OR and methanol are largely co-extensive, with total extents between 10 and 30 mpc (milliparsec). Elongated morphologies are common in both the OR and methano