blank-sky region for use in the double subtraction method (an annulus between 320 and 480 arcsec as described in section \[background\],(region 4 in Fig. \[image\]).

5.  The background region used for region 3 (region 5).

6.  The AGN and lobes

We extracted the AGN spectrum by taking a circular region with a radius of 25 arcsec (38.25 kpc) around the AGN and used a local annulus with a radius of 59 arcsec (90.27 kpc) for the background. We also excluded a 12 arcsec (18.36 kpc) region to the North-East of the AGN to remove a point source that would have affected our results. The same method was used for the lobes, but instead of a circular region, we took a rectangular region of length 247 arcsec (378 kpc) by 130 arcsec (199 kpc). The regions for the AGN and the region to the North-East of the AGN were excluded as well. We used the double subtraction method to determine the background for this region.

Double subtraction was also used for our two large-scale regions, intended to measure the temperature of group-scale gas which can be detected by eye in heavily smoothed images out to 320 arcsec. Our choice of a 