Distribution of corrected Hubble residuals per Σ_Hα group (top, as in Fig. 6) and per mode (bottom) for the full sample. In the lower panel, the open-red and the filled-gray histograms represent the corrected Hubble residual distributions of M₁ and M₂, respectively. By definition of the modes, the red histogram corresponds to the stack of the blue distribution with the open histogram above (see the top-panel), while the filled-gray histogram corresponds to the part of the open histogram below . Colored solid lines (red for M₁ and black for M₂) show the best fit by a normal distribution (with 3σ clipping). Fit parameters are quoted beside each Gaussian.