Cumulative density function of the mean amplitude of all extrema, maxima (red) and minima (blue), derived from simulations, compared to the equivalent values observed for the SMICA CMB temperature map. The upper panel shows the peak mean amplitudes for maps filtered with a GAUSS kernel of 40′ FWHM. The lower panel shows the corresponding peak CDF for an SSG84 kernel of 800′ FWHM. Similar results are obtained for the other component separation methods. Since the filter kernel normalization is free, and the pre-whitened map to which the filter is applied is dimensionless, the plots are essentially in arbitrary units.