We have used the Shanghai Tianma Radio Telescope to search for three OH transitions at 4.7GHz toward 155 northern star formation regions. We detect 4.7GHz OH masers in 18 star formation regions, 8 of which are reported here for the first time. From these 18 sources, we detect 6 4660MHz masers, 13 4765MHz masers, and no 4750MHz masers. A further 1 source (Sgr B2N) has been re-detected with broad quasi-thermal emission in all three OH lines. W49SW was re-detected with broad quasi-thermal emission at both 4660 and 4750MHz. One source (W31, G010.626-0.387) was re-detected with quasi-thermal emission at both 4750 and 4765MHz. One source (G005.885-0.392) was first detected with quasi-thermal emission at 4660MHz. We have investigated the associations between the detected 4.7GHz OH masers with ground-state OH masers near 1.7GHz, 6.7GHz methanol masers and 22GHz water masers reported in the literature. We find that the presence of 1665MHz OH masers is a better indicator of the presence of 4.7GHz OH masers than 1720MHz OH masers. The majority of the 4.7GHz OH masers are associated with 6.7GHz methanol and/or 22GHz water masers. We have compared the characteristics of our detections with those reported previously in the literature and found that only five sources are fairly stable.

Cone search capability for table J/ApJ/928/129/table1 (Sources searched for 4.7GHz OH masers)