SIMBAD references

We report the discovery of H₂ line emission associated with 6.67-GHz methanol maser emission in massive star-forming regions. In our UNSWIRF/AAT observations, H₂ 1-0 S(1) line emission was found associated with an ultracompact Hii region IRAS 14567-5846 and isolated methanol maser sites in G318.95-0.20, IRAS 15278-5620 and IRAS 16076-5134. Owing to the lack of radio continuum in the latter three sources, we argue that their H₂ emission is shock excited, while it is UV-fluorescently excited in IRAS 14567-5846. Within the positional uncertainties of 3arcsec, the maser sites correspond to the location of infrared sources. We suggest that 6.67-GHz methanol maser emission is associated with hot molecular cores, and propose an evolutionary sequence of events for the process of massive star formation.