Cosmic-ray smoothing experiment. Panels show the spatially resolved radio-SFR relation prior to the smoothing (left panels) and following the smoothing of the Σ_SFR maps (right panels). The vertical axis shows the radio continuum Σ_SFR values converted with a constant factor from the radio continuum intensity. The horizontal axis shows the hybrid Σ_SFR values. Each data point represents a pixel of 1.2 × 1.2 kpc². Data points are colour-coded with the non-thermal radio spectral index: data points with α < −0.85 in blue, data points with −0.85 < α < −0.65 in green, and data points with −0.65 < α < −0.50 in red. Data points with α > −0.5 are shown as outliers and not considered for the data analysis; they are shown in grey. The best-fitting relation is shown as a solid line and the Condon relation is shown as a dashed line. Smoothing of the Σ_SFR maps allows us to reach a slope of 1 for the radio-SFR relation. The vertical displacement is deviation from the integrated radio-SFR relation. From top to bottom, frequencies are 54 MHz (in combination with 144 MHz, panels a and b), 144 MHz (in combination with 54 MHz, panels c and d), and 1365 MHz (in combination with 144 MHz, panels e and f).