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Session 21 - Jets, H-H Objects, and Molecular Outflows.
Display session, Monday, January 15
North Banquet Hall, Convention Center
HH objects have long been known to exhibit emission from the near-infrared lines of shocked molecular hydrogen. Imaging of these lines has shown that the distribution of the 1-0 S line is very similar to that of low-excitation optical lines. This is somewhat puzzling, since the shocks which excite the optical emission should dissociate the H_2. In order to resolve this puzzle, we need to have as much high spatial-resolution information as possible about H_2 in these objects, including observations of high- and low-excitation objects, and imaging of H_2 in more than one line.
We present the results of a continuing survey of HH objects for shocked molecular hydrogen emission. The objects are first imaged in the 1-0 S(1) 2.12 \mum line, and if detected are then imaged in the 2-1 S(1) 2.25 \mum line. The ratio of these two lines is not only an important discriminator of shock-vs-fluorescent emission, but is also a temperature indicator in shocked gas. In some objects the 1.64 \mum line of [FeII] is also observed. This line traces shocks similar in excitation to those which display [SII] 6716/6730 Å\ emission, but suffers less extinction than the [SII].
