Spectral age maps of J1021+1216 outer and inner double presented as color maps, with color bars representing the scales given next to each panel. Each panel is labeled from a to h in the top-right corner. In panels a–d, a 1.4 GHz contour map is overlaid for reference. The contour levels are (3, 9, 39)×0.35 mJy/beam. The size of the circular beam for the color and contour maps is 45″. In panels e–h a 323 MHz contour map was overlaid for reference. The contour levels are (3, 9, 39)×0.23 mJy/beam. The size of the circular beam for the color and contour maps is 13″. Panel a: Spectral age map of the whole RG. The gray line marks a slice through the source. The age profile, which was created this way, is shown in Fig. 7. Panel b: χ_red² map of the whole RG. The regions with χ_red² > 3.02 (99% confidence interval) are marked in red. Panel c: Spectral age 1σ upper error map of the whole RG. Panel d: Spectral age 1σ lower error map of the whole RG. Panel e: Spectral age map of the inner double. The gray line marks a slice through the source. The age profile, which was created this way, is shown in Fig. 7. Panel f: χ_red² map of the inner double. The regions with χ_red² > 3.02 (99% confidence interval) are marked in red. Panel g: Spectral age 1σ upper error map of the inner double. Panel h: Spectral age 1σ lower error map of the inner double.