Abstract
The authors report observations of the H110α and H138β recombination lines and of the J = 1-0 rotational transition of CO toward H II regions suspected of having narrow radio recombination lines from the results of surveys with modest signal-to-noise ratio. Only one of the sources studied G 0.6-0.6, was found to have anomalously narrow recombination line emission, Δυ(H110α) ≅ 14.4±0.4 km s-1. However, as a group, the sources studied have lines that are systematically narrower than "typical" H II regions. G 0.6-0.6 and G 19.5+0.1 are also unusual in having very little "turbulent" broadening in their recombination line emission. Another H II region in the sample, G 19.6-0.1, seems to have created a blister-like cavity in its associated molecular cloud.
