Left: integrated radio spectra of relics R1, R2, R3, and R4. Dashed lines are the fitted power-law with indices given in Table 3. Regions used to obtained the integrated flux densities of all four relics are shown in the right panel of Fig. 7. Right: spectral index map of the main relic R1 between 675 MHz and 1.5 GHz at 10″ resolution (corresponding to IM6 and IM11 in Table 2), showing a clear spectral index gradient across the entire relic. Contour levels are drawn at [1, 2, 4, 8, …] × 3.5 σ_rms, and are from the uGMRT Band 4 image.