RGS Spectroscopy of the Cygnus Loop XA knot

RGS spectroscopy of a bright knot in one of the nearest supernova remnants(the Cygnus Loop), together with high quality EPIC images and spectra, providesa unique opportunity to understand the nature of the supernova remnant/interstellar medium interaction. By making use of the EPIC images as templates forthe dispersed image of the knot environs, the O VII lines will be extracted.The O VII forbidden to resonant line ratio and the O VIII to O VII line ratioallow the determination of the physical length of the emitting region alongthe line of sight. The EPIC spectra will allow accurate determination of thetemperature distribution over this portion of the supernova remnant. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]