Observations of CO J = 3→2 emission from molecular clouds

Extensive spectral observations in the CO J = 3→2 line have been made toward a sample of hot-centered molecular clouds which exhibit self-absorption or high-velocity gas. The observations were made with the 3.8-m United Kingdom Infrared Telescope (UKIRT) with the QMC and UKIRT submillimeter heterodyne receivers. The spectra are generally similar to observations in the lower CO transitions, though there is a tendency for enhanced red-shifted high velocity gas to be present. Mapping observations with high angular resolution have revealed accurate positions and intensity profiles for a number of sources. NGC 2068 and NGC 2023 are resolved, isolated, and symmetrical clouds, while NGC 1333 and NGC 2024 are more complex areas, containing multiple hotspots