Distribution of spectral index (α) values for different frequency choices for the case of 3Dang_ref is shown here for a line-of-sight angle of (70° ,0°). The frequencies used to generate these maps are 0.240–0.610 GHz (left), 0.240–5.0 GHz (middle), and 5.0–43.0 GHz (right), respectively. The steepening of α values with increasing frequency choices in the wings is expected due to synchrotron cooling. The presence of flatter α patches (particularly in the wings) are prominent if the chosen frequencies are in the low-frequency regime (indication of particle re-energisation).