WARM NEUTRAL HALOS AROUND MOLECULAR CLOUDS .2. H-I AND CO (J = 1-0) OBSERVATIONS

Observational data are presented relating to the boundary regions between dense, molecular clouds and the more diffuse atomic gas. The data set consists of H I 21 cm and CO (J = 1-0) strip maps in 14 molecule clouds which traverse 62 known CO cloud boundaries. The angular lengths of the strips range from 0.5-degrees to several degrees of arc, which is generally adequate to eliminate confusion with background (and foreground) H I. Most of the crossed boundaries (49 of 62) show clear evidence for the presence of H I emission maxima, or halos, lying outside the molecular clouds' gas. There is also general evidence for limb brightening in the CO emission.