Fabry-Perot imaging of molecular hydrogen emission on Orion-KL region

Abstract

A continuum-subtracted image of the H2 nu = 1 goes to 0 S(1) line covering the central 4 min square portion of the Orion-KL region, has been obtained using a wide-field Fabry-Perot imager at the Communication Research Laboratoy 1.5 m telescope. Nine H2 peaks (including four newly identified) are found in te core, as well as a curved, bridgelike structure that enroaches on the inner edge of the disk structure observed in CS (J = 1 goes to 0) emission. This existence of the bridge indicates that the outflow from IRc2 occurs not only toward the bipolar axis but also toward the disk, and suggests channeling by the disk of a more or less isotropics flow from IRc2 into a bipolar flow. Outside the core, where finger-like features of H2 emission are seen, we identify 43 hot H2 clumps. These are located along filamentary structures seen in CS (J = 1 goes to 0) maps and avoid peaks of CS intensity. The geometrical thickness of the hot H2 in these features is much smaller than their typical dimension. We conclude that the H2 emission from the clumps is radiated at the surface of the CS filaments, implying that outflow form IRc2 shocks the H2 at the surfaces. From comparison of polarization measurements of Burton et al. (1991) with the present meausrements, as well as from discussion of the energetics, we rule out the possibility that the H2 clumps are due to reflection.