X-ray shadow experiments with XMM

GT Xray shadow experiments are important, because they help us to determinethe distribution of the Xray plasma in our Galaxy. Recent results (Kerp et al.1997, Pietz et al. 1997) indicate that our Galaxy has an extended Xray halo.This halo plasma accounts for the 1/4 keV as well as for the 3/4 keV backgroundradiation. The aim of this proposal is to improve our view of the Xray backgr.Based on our experience with the ROSAT PSPC, we will use EPIC imaging spectra toderive the 3D composition of Xray mietting and absorbing matter distributedalong the line of sight by analysing Xray colours and to determine whether theGalactic halo plasma or a steepening of the extragalactic power law causes theobserved increase in the background intensity towards lower photon energies. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]