(upper) and (lower) statistics as a function of circle radius α for the PlanckCommander (short-dashed red line), NILC (long dashed orange line), SEVEM (dot-dashed green line), and SMICA (three dot-dashed blue line) 2015 temperature maps. The dotted line shows the false detection level established such that fewer than 1% of 300 Monte Carlo simulations of the SMICA CMB temperature map, smoothed and masked in the same way as the data, would yield a false event. The peak at 90° corresponds to a match between two copies of the same circle of radius 90° centred around two antipodal points.