THE SPATIAL INTENSITY DISTRIBUTION OF THE UV-LIGHT IN HH OBJECTS - REVISITED

Simple kinematical bow shock models have successfully explained many o f the observed features in Herbig-Haro objects. It is shown that simil ar models can be applied to the spatial intensity distribution of the UV lines observed by IUE. Archival IUE spectra have been used for the HH 1, HH 2(H+A'), HR 2(G+B), HH 24A, HH 32A, HH 43(A+B+C), and HH 47A objects, where the brightest UV lines (C IV lambda 1549, Si III lambda 1891, C III] lambda 1909, C II] lambda 2326, Mg II lambda 2799) were studied, as well as the UV continuum (modeled by the hydrogen two-phot on continuum). The quality of the IUE data is rather limited due to th e broad point spread function and the low signal-to-noise, and therefo re the models were degraded to make them comparable to the observation s. The physical parameters used in the models were obtained from previ ous optical studies and varied accordingly to match the observations, but within the known uncertainties. The objects were modeled by a sing le bow shock model (i.e., HH 1, HH 24A, HH 32A, and HH 47A) or the sup erposition of two (i.e., HH 2(H+A') and HH 2(G+B) or more (i.e., HH 43 (A+B+C)) of them. The idea was to take into account the complexity of the morphology of these objects, and the contribution to the UV light from different condensations within the IUE aperture.