Synchrotron latitude profiles for the data and the updated models’ ensemble average. The observables are averaged over a range of longitudes for a given latitude bin, and on the left is total intensity and on the right polarized intensity. The top shows the inner Galaxy (i.e., −90° <l< 90°), while the bottom shows the third quadrant (180° <l< 270°, i.e., the outer Galaxy excluding the Fan region). The dotted coloured lines show the model mean plus or minus the expected variation predicted by the models (though these are often too close to the solid lines to be visible). This variation is also the σ used to compute the significance of the residuals in the bottom panel of each row. The dashed curves show the profiles excluding the loops and spurs discussed in Sect. 3.4.3. The grey band shows the ± 3 K zero-level uncertainty of the data at 408 MHz extrapolated with β = −3.1.