Pipeline-estimated background values on MOS (left) and PN (right) detectors, in the soft band, as seen in the simulations. Curves from bottom to top stand for background ratios B equal to 0.1, 0.25, 0.5, 1, 2, 4 and 8. This plot shows how the local background estimate output of the detection algorithm can be related to the background ratio parameter introduced in the simulations. The error bars represent 1-σ standard variation computed from the source sample. The vertical lines correspond to bounds of our equal-area off-axis bins. Only the results for 10 ks are displayed and similar relations are extracted for 7, 20, 40 and 80 ks pointings.