Observations of PKS 1209-5152: A Cygnus Loop SiblingquestionMark

The number of SNRs older than 10,000 yr wellstudied in Xrays is small, due tothe observational difficulties of mapping low surface brightness thermal plasmaswith temperatures of a few tenths of a keV with interstellar absorption. Wepropose to observe the bright limb of G296.5+10.0, also known as PKS 120951/52,with the EPIC instruments. We will produce a map of the bright, soft, thermalemission along the southeastern shell, to be compared with optical, radio, andCO continuum maps. We will characterize the temperature and density variationsin the shell, which result from interactions between the forward shock andstructures in the ISM. A more complete understanding of the old, very large SNRswill help us understand the feedback role that SNe play in the evolution of the Galactic ISM. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]