Spectral index maps of Nest200047, as described in Sect. 3.2. Central panel: Spectral index map of the entire source between 400−815 MHz with a resolution of 25 arcsec. Top panels: Spectral index maps of the northern bubbles between frequencies 53−400 MHz (left) and 700−1280 MHz (right), with a resolution of 12 arcsec. Right panels: Spectral index maps of the central jets–bubbles between 400−700 MHz (top) and 700−1518 MHz (bottom), with a resolution of 6 arcsec. The black contours always trace the emission at the lowest frequency included in the map starting from 3σ.