files were vignetting-corrected and filtered in the same way as the 3C452 observations and were rotated to be at the same angle as the dataset using the SAS task [*attcalc*]{}. Using the scaling factors described in Section \[background\], we were then able to subtract a position-dependent background correction from each radial bin. The X-ray background contribution was subtracted using the outermost annulus of our profile (region 4 in figure \[image\]) Finally, the radial profiles for each camera were combined to produce a profile of net count rate per unit area.

We then fitted a model consisting of a point source, with free normalization, and a $\beta$ model with free $\beta$, core radius and normalization to the radial profile. Each component of the model was convolved with an [*XMM-Newton*]{} point spread function derived from the combined point-spread functions of the three cameras, suitably weighted. The fitting process used a Markov-Chain Monte-Carlo algorithm described in detail in @gch11, an updated version of the method used by @chbwl08.

The best-fitting $\beta$ model, ($\chi^2/{\rm dof} = 66/9$) has $\beta = 0.53\pm0.02$ and the core radius was $21.98\pm1.05$ arcsec. Figure \[profile\] shows the surface brightness profile with the best-fitting model. Although it would have been 