NICMOS observations of shocked H2 in orion

HST NICMOS narrowband images of the shocked molecular hydrogen emission in OMC-1 are analyzed to reveal new information on the BN/KL outflow. The outstanding morphological feature of this region is the array of molecular hydrogen "fingers'' emanating from the general vicinity of IRc2 and the presence of several Herbig-Haro objects. The NICMOS images appear to resolve individual shock fronts. This work is a more quantitative and detailed analysis of our data from a previous paper. Line strengths for the H-2 1 - 0 S( 4) plus 2 - 1 S( 6) lines at 1.89 mu m are estimated from measurements with the Paschen-alpha continuum filter F190N at 1.90 mu m and continuum measurements at 1.66 and 2.15 mu m. We compare the observed H-2 line strengths and ratios of the 1.89 and 2.12 mu m 1 - 0 S( 1) lines with models for molecular cloud shock waves. Most of the data cannot be fit by J-shocks but are well matched by C-shocks with shock velocities in the range of 20 - 45 km s(-1) and preshock densities of 104 - 106 cm(-3), similar to values obtained in larger beam studies which averaged over many shocks. There is also some evidence that shocks with higher densities have lower velocities.