EVIDENCE FOR LARGE-SCALE EXPANDING MOTIONS WITHIN THE ORION A MOLECULAR CLOUD

Images of the Orion A molecular cloud constructed from spectra of (CO)-C-12 J = 1-0 emission observed with the FCRAO 14 m antenna are presented. An inspection of the kinematics of the Orion A cloud reveals several regions with large-scale expanding motions manifest by nearly circular emission features with radii 10'-26' (1.0-2.6 pc) and secondary velocity components which are shifted 2-3 km s-1 from the ambient cloud velocity. The presence of these large-scale features, which partially overlap with each other in projection, suggests that the diffuse molecular component of the Orion A cloud as traced by CO emission has been significantly disrupted by events associated with the energetic star forming activity within its domain.