The following document lists the file abstract/RTIMMERM_LVS2.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
===================================================================== ==> In this proposal, more time is being requested for DJAFFE.LVS. ===================================================================== This proposal is a continuation of the OT proposal DJAFFE.LVS. The new proposal focuses on very low-continuum outflows that had to be omitted from our earlier observing program. The goals of this proposal are to characterize the physical nature and emergent spectrum of low-velocity shocks (LVS), with shock speeds of or below 20 km/s, in dense outflow-sources and to test models of MHD shocks in the low-velocity range, where there are hitherto untested. High-velocity shocks from protostellar outflows, HH objects, and SNR were subject of the Central Programs. These observations, however, suffered in loss of sensitivity due to the strong IR continuum of most sources, as they had to be performed with the less sensitive Fabry-Perot (FP) or with low line-to-continuum (L/C) ratios in the grating mode. There were, with exception of our proposal, no corresponding plans to study shocks in the low-velocity range. LVS's are important as signposts of injection and dissipation of turbulent energy in the dense ISM. The current phase of our work concentrates on the issue of dissipation. We shall examine a small sample of protostellar flows for which we selected a set of diagnostic lines: the OI 63, 145 mu and some H2 rotational transitions. H2 ro-vibrational lines and that of CII 157 mu will be observed to test for high-velocity shock components and PDR contamination. We focus our attention on oxygen-chemistry in shocked gas through observations of line emission of H2O, OH, and O2. First ISO results showed that H2O, contrary to predictions, is NOT always the most important coolant in shocks. We want to test this for LVS's. Our targets have been chosen to avoid regions with high-velocity shocks, strong PDR emission, or IR continuum radiation. They are far away from the driving sources. Studies of the sources have shown they are nearby protostars with well-developed outflows. We will point ISO at the snowplowed gas crashing into the ambient ISM at modest shock speeds, far from the central sources. The results of our previous proposal demonstrated that the proposed lines are detectable.