Histograms of the values of the FP-like coefficients a, b, and c. The green, blue, and red colors correspond to the three solutions found for β, respectively. The gray band in each plot marks the region of the coefficients obtained by D’Onofrio et al. (2008) for the fit of the FP of the different WINGS clusters. The dashed black lines are the average values of the FP-like coefficients obtained considering only solutions β₂ (blue) and β₃ (red), and discarding solution β₁ (green) which clearly does not fit with the intervals of the measured FP coefficients.