Kinematics of Orion-KL - Aperture synthesis maps of 86 GHz SO emission

Abstract

The Hat Creek inteferometer was used to map the 86 GHz, 2(2)-1(1) line of SO toward the Kleinmann-Low Nebula with an angular resolution of 6 x 6 arcsec. The 'pedestal' component of the SO emission arises from a region with a FWHM size of 11 x 19 arcsec, centered within a few arcsec of the IR source IFc2. This region is extended in a NE-SW direction, perpendicular to the two lobes of vibrationally excited H2 emission. The peak brightness of the SO line is about 50 K. The maps show evidence of a systematic velocity structure across KL. Emission to the NW of IRc2 tends to be redshifted, while emission to the SE is blueshifted. The velocity shifts are consistent with a model in which the SO emission arises from an expanding 'doughnut' of gas centered near IRc2.