Spectro-polarimetry of the Molecular Hydrogen LIne Emission from OMC-1

The profile of the H2 1-0 S(1) line has been observed at 35 km/s velocit resolution at several locations within OMC-1, including in the molecular hydrogen reflection nebula. The profiles have been deconvolved from instrumental effect using the "maximum-entropy" method. In addition, at four locations (Peaks 1,2 5 and IRc2) the polarization profile across the line has been measured. All lin profiles are smooth at the resolution observed, showing no evidence for bein composed of discrete components. In the NW lobe associated with Peak 1, a profiles have an extended blue wing, with total velocity extent upto 150 km/s Elsewhere in OMC-1 (the SE lobe and the H2 reflection nebula) the line profile are symmetric with typical widths 50-70 km/s. There is evidence for a chang in polarization with velocity at Peak 5, and marginal evidence for a change a Peak 2. The percentage polarization and position angle appear to decrease wit increasing blue-shifted velocity. There is no evidence in the data for a change i polarization with velocity at Peak 1 or IRc2. The data are discussed in terms o a model for the H2 line formation; in the model the emission originates i discrete clumps moving at different velocities. The extended blue wing ma come from fast-moving clumps embedded in a wind, and the line core from shocked gas at the edges of an outflow cavity. There is no evidence to support a upscattering model of line photons as a mechanism for wing formation, althoug higher velocity resolution observations are required to adequately address th question. A polarization model for OMC-1 is presented.