Spectral index map of J0011+3217 between 144 MHz and 607 MHz of the peculiar radio galaxy J0011+3217. Left: A LoTSS DR2 image at 144 MHz (with 20″ × 20″ resolution) is overlaid in contours (levels: 0.23, 0.45, 0.75, 1.17, 1.75, 2.57, 3.72, 5.33, 7.58, 10.7, 15.1, 21.3, 30.0, 42.1, and 59.0 mJy beam⁻¹) with the spectral index map of J0011+3217. Right: Spectral index error map of J0011+3217 between 144 MHz and 607 MHz.