Power spectra of residual images for an increasing number of subtracted sources. From top to bottom: initial image without subtracting any source (Fig. 11); after subtracting 15 sources (Fig. 12); after subtracting 50 sources (Fig. 13); after the whole sky model is subtracted (Fig. 14). The error bars are at the 1σ confidence level. The dashed line represents the noise power spectrum.