Observations of the 2π3/2, J = 7/2 State of OH

Abstract

The 6 GHz transitions of the 2π3/2, J = 5/2 excited state of OH are present in emission in the direction of several OH-emission regions (Rickard et al. 1975; Knowles et al. 1976), and in absorption in compact thermal sources (Gardner and Whiteoak 1975). This has suggested that transitions in the next highest state near 13 GHz (J = 7/2) might also be widely observable. A single detection has already been reported in W3OH by Turner et al. (1970). In this paper we report the observation of narrow-band emission in several other sources.