Top: result of the single-mesh point-to-point analysis. The slope of the best-fitting power-law is reported in the legend, and the insert presents the sampling grid overlaid on the low-resolution 144 MHz map (Fig. 1). The blue-shaded region indicates the 90% confidence interval of the fit. Bottom: slope index distributions produced by the MCptp analysis at 0.144 MHz as well as 1.4 and 5.5 GHz (from Ignesti et al. 2020). The mean and standard deviation of each distribution is shown in the labels.