Shock-cloud interactions in the Vela SNR: preliminary results of an XMM-Newton observation

The study of the clumpy and irregular features in the X-ray emission of middle-aged supernova remnants shells allows us to shed light on the various characteristic of the interstellar medium, like its structure and composition. We have observed with XMM-Newton a small knot in the Vela SNR, which previous ROSAT studies have indicated as one of the best examples of an interaction between the SNR shock and an isolated cloud. We present preliminary results of this study. Thanks to the combination of good spectral and spatial resolution of the EPIC camera, we have realized maps of the X-ray emission in three different bands, pinpointing the contribution from different spatial regions. We have also studied the relation between the mean photon energy in a 10 arcsec/ pixel image and the pixel count rate, arguing that at least two kinds of isobaric structures (a small isolated cloud and a larger feature) can be identified, both of which have interacted with a shock and both with their own thermal structure. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.