Radio color-color diagram of the halo in 1RXS J0603.3+4214 using the spectral indices extracted in 15″ × 15″ boxes shown in the left panel of Fig. 6. The contaminated regions in halo C are shown with an orange circle. The relic+halo (red) indicate combined emission from the B1 region of the Toothbrush and the halo. The halo C points are clustered around the power-law line, indicating no sign of spectral curvature. The relic+halo points lie in the concave part of the color-color plot, suggesting superposition of the halo and the relic emission.