The high velocity CO outflow in Orion.

Maps of the CO outflow in Orion KL with resolutions of 21 arcsec (at 115.271 GHz) in the J = 1-0 line, and of 14 arcsec (at 230.538 GHz) in the J = 2-1 line are presented. For CO outflow speeds larger than 20 km/s, the angular sizes of the emission regions are constant, with a FWHP of about 24 arcsec. The noted distribution of red-shifted CO deviates from circular shape, and examination of size, position, and velocity does not suggest a constant velocity flow. Using the Case 1 model of Cabrit and Bertout (1986), data indicate that the outflow axis is within 30 deg of the line-of-sight, that the flow is accelerated, and that the flow age is 20,000 years. Results may give support for a clumped outflow, though the indication that the 2-1 and 1-0 lines are optically thin in the high velocity ranges indicates that such clumps may only be a small part of the outflowing gas.