VELOCITY-FIELD OF THE ORION-KL REGION IN MOLECULAR-HYDROGEN EMISSION

The velocity field of the H-2 v = 1-0 S(1) line in the Orion-KL region was measured using a Fabry-Perot imager with 24 km s(-1) resolution. The peak velocity is bluest near the central source, approaching the r est velocity of the ambient molecular cloud with increasing distance f rom the center. This spatial variation of the peak velocity can be exp lained by an expanding spherical shell. The radius of the shell is coi ncident with the extent of the high-velocity molecular outflow, which drives the shell expansion. Blue wings, which reflect the motion of sh ocked gas in the outflow, show also an approximately spherical expansi on. These results imply a more or less originally isotropic flow from the central source. A curved, bridgelike structure that encroaches on the inner edge of a disk structure is noticeable in the peak velocity map, with the bluest peak velocities. This structure is considered to be a region where the isotropic outflow from the central source strong ly collides with the inner edge of the disk, which imposes a bipolar a ppearance on the flow.