Results obtained using increasing luminosity thresholds for the X-ray point sources. Top panel: distribution of X-ray point sources in galaxy clusters as a function of radius in units of . Bottom panel: total surface density of X-ray point sources in galaxy clusters divided by the optical galaxy profile. In both panels, the expected number of sources in the field has been subtracted statistically from each annulus. Error bars indicate the 1σ confidence limits for small numbers of events in astrophysical data.