Maps of the 36 GHz methanol emission

In most sources, the emission consists in one or several narrow (maser) features superimposed on a broader, presumably quasi-thermal component. The line shapes and positions of the narrow features are often similar to those observed in the other ClassI methanol maser transitions (at 25, 44, 84 and 95GHz), but with some exceptions.

Our observations confirm that, unlike the strong ClassII methanol masers (at 12.2, and 6.6GHz), the ClassI methanol masers are offset from the compact HII regions, infrared sources and OH/H_2_O masers. In outflow sources, these are located at the edge of the molecular lobes.