Observations & fitted parameters of OH maser emission

In total, we detect 44 6.0GHz OH masers, 8 of which are new detections (one at 6016MHz, two at 6030MHz, and five at 6035MHz). Of these 44 detected 6.0GHz OH masers, 13 sites exhibit 6030MHz OH masers, all 44 sites show the 6035MHz transition, one site (G009.620+0.194) has the only 6016MHz OH maser, and one site (W3(OH)) shows the only 6049MHz OH maser.

The 6016MHz OH maser is the first OH maser of this transition detected in star formation regions. Investigations of the association between 6030/6035MHz OH masers with 1665MHz ground-state OH, 6.7GHz methanol, and 22GHz water masers show that 1665MHz OH masers are good indicators of 6.0GHz OH masers (29% detection rate), which is consistent with previous results. The majority (more than 77%) of 6030 and 6035MHz OH masers are associated with 6.7GHz methanol and/or 22GHz water masers.