Spectral index and spectral curvature maps for pixels with surface brightness greater than 7σ and 3σ, respectively, in all of the input maps. We used the averaged low-resolution LOFAR image (Table 2). Overlaid are LOFAR contour levels spanning the interval between −10σ and 60σ, with a step of 10σ, where σ = 4 mJy beam^-1. The black cross indicates the position of the host galaxy.