1.4 GHz continuum maps. From left to right: Observed radio continuum, best-fit model from pPyBDSF, and the residuals in terms of data-model. The contour levels, with the lowest corresponding to 3σ, are given by the colour bar at the top. A 5 kpc reference line is given in the bottom left corner. In the central panel we indicate with blue arrows the locations of the core (C), the two inner hotspots (I), and the two outer hotspots (O). In the right panel we highlight the edge-brightening of the bubbles with the cyan dashed contours, corresponding to a flux density of 10 μJy beam⁻¹.