Confirmation of the exclusive association between 6.7-GHz methanol masers and high-mass star formation regions

Abstract

Recently, a comparison between the locations of 6.7-GHz methanol masers and dust continuum emission has renewed speculation that these masers can be associated with evolved stars. The implication of such a scenario would be profound, especially for the interpretation of large surveys for 6.7-GHz masers, individual studies where high-mass star formation has been inferred from the presence of 6.7-GHz methanol masers and for the pumping mechanisms of these masers. We have investigated the two instances where 6.7-GHz methanol masers have been explicitly suggested to be associated with evolved stars, and we find the first to be associated with a standard high-mass star formation region, and the second to be a spurious detection.We also find no evidence to suggest that the methanol maser action can be supported in the environments of evolved stars.We thereby confirm their exclusive association with high-mass star formation regions. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.