A SILVER LINING FOR THE COALSACK NEBULA comma A HOT PLASMA/COLD CLOUD INTERFACE

We propose to observe a probable hot plasma/cold cloud Xray emitting interfaceregion surrounding the Coalsack Nebula. Such an interface will provide a nearlyunique insight into the physical parameters of transition regions, which are afeature of models of the interstellar medium but are not observed (except inactive SNR shock fronts). The motivation for the observation is threefold, toverify the existence of the Xray bright transition region as observed with inROSAT data, determine the origin of the Xray emitting plasma, and determine thephysical state of the plasma. Specifically, to answer the question whether theinterface region between the cloud and the surrounding hot gas is experiencingevaporation, condensation, or turbulent mixing. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]