CCA estimates of the AME frequency spectrum in the region of interest for real data (left panels) and simulated data (right panels). Top: estimated spectra including 1σ errors. Middle and bottom: histograms of the spectral parameters m₆₀ and ν_p on N_side = 16 estimated spectral index maps. For the simulated case (right panels) we considered two convex spectra peaking at 19 GHz and 26 GHz and a power-law model. Top right: the true inputs are shown as solid black lines (power-law) with triangles (19 GHz peak) and squares (26 GHz peak) and the estimates as shaded areas. The blue and red colours show estimates derived by exploiting the free-free templates FF₁ and FF₂ described in Appendix C. Middle and bottom-right panels: the true inputs are shown as solid and dotted vertical lines for the simulations peaking at 26 GHz and 19 GHz respectively; the blue dot-dashed and red solid histograms show the estimates obtained using the FF₁ and FF₂ templates, and the black dashed lines show the estimates for the 19 GHz input spectrum.