Radio surface brightness profiles of T1 and T2 normalised to the peak value within T1-A and T2-A, respectively. Left panels: profiles of T1 (middle) and T2 (bottom) at 143 MHz (resolution 9″ × 6″). The sampling boxes are shown in the top panels and have a width of 10″. Right panels: comparison of profiles at 50 (brown), 143 (yellow), 323 (green), 608 (light blue), and 1284 (magenta) MHz. The resolution of the images and the width of the sampling boxes (not shown) are 14″. In middle and bottom panels, the vertical lines indicate the boundaries of sub-regions as in Fig. 2.