Radio and X-ray surface-brightness profile of A2061. Top left panel: 80′′ radio map at 144 MHz with residual sources masked is shown via a pink colour scale. We show the 2, 3, 5, 10-σ_rms contour levels in purple and the 20, 30-σ_rms contour level in white. The mean radio brightness is computed inside the blue region. The width of the elliptical annuli along the major axis is ∼2 times the beam size (80′′). The 2.5r_x area is delimited by the dashed green line. Bottom left panel: comparison between the average surface brightness measured in each blue bin (the magenta data points, with 1σ uncertainties) with the model profile from the best-fit analysis performed with HALO-FDCA (solid cyan line, with 2σ uncertainties). Beyond ∼2.5r_x (dashed green line), the average surface brightness is persistently higher than the best-fit radio-halo model due to the NE extension. Top right panel: smoothed XMM-Newton X-ray map is shown in blue colour scale. The contour levels from the radio emission are overlaid in purple, and the X-ray point sources (green circles) are masked. The X-ray surface brightness is computed inside the magenta slices, centred on the radio halo and covering the NE extension. We compare this sector with the yellow slice, in a direction offset from the extension. The width of the circular sectors is one beam size (80′′). Bottom right panel: the two profiles extracted from the different sectors are shown in magenta and yellow points. In the NE direction, we note a bump in the profile associated with the X-ray plume that is followed by an excess at larger radii. On the contrary, there is no evidence of excess at the same distances from the centre in the yellow sector. The background level in each sector is shown with magenta and yellow dashed lines.