Left panel: exposure corrected and background subtracted count map in the 0.6–6 keV energy band of the 2015 XMM-Newton observation. The image is smoothed with a Gaussian of 20 arcsec kernel radius. The red contours are the results of the Canny edge detection algorithm discussed in the main text. The white boxes represent the regions used to extract the radial profiles shown in Fig. 2 and the white and red crosses the 2002 and 2015 pointing positions. Right panel: edges detected in the 2002 (black) and 2015 (red) observations. The point sources discussed in the image registration process are labeled Src 1 to Src 6.