B2 fluorescence from molecular outflows

Shock wave modeling requires a great number of Hp lines to be observed so that we can infer critical shock parameters like the shock velocity, orientation (for bows), pre-shock pressure (for J-shocks), magnetic fields (for C-shocks) from the observed Hz population densities. Recent studies of some of these objects have shown that shocks alone cannot be responsible for the whole H-2 emission. We illustrate this point by showing that in HH 7 and DR 21 the H-2 emission can be simply explained by a combined model consisting of a bow C-shock transition layer plus a PDR component that can excite the higher H-2 energy levels and thus produce fluorescence H-2 emission.