Probability distributions of finding statistics P_S smaller than the values set by the cluster pair RXC_J1659−J1702 (upper panel) and RXC_J1155−J1156 (lower panel) for scenarios with B₀ as labelled. The vertical lines show the P_S values computed without any injection from Im_empty (red dotted) or Im_diffuse (blue dashed). The black and grey lines show results for source injection performed respectively in the visibility and image domains. The insets show a zoom-in on the bins where .