Milliarcsecond maps of 12 GHz methanol masers

Abstract

Extremely strong methanol masers at 12 GHz have recently been discovered in sites of star formation. Here we report the first maps of these masers, which were obtained using a 275-km baseline radio-linked interferometer. The region occupied by methanol masers appears to have a similar extent to that of the well studied OH masers, and presumably surrounds the same newly formed stars. But individual clusters appear more compact than their OH counterparts, and, in contrast to the OH, appear in several cases to be distributed along a line or curve, suggesting accretion disks, shock fronts, or jets. This suggests that the methanol masers require conditions different from those that foster OH masers, and their detailed distribution promises to cast further light on the kinematics of the star-forming gas.