Synchrotron SED using our radial sphere implementation constructed with parameters m = 1, n = 2, x = 50 and α = 1 as formulated for a power-law sphere in Band & Grindlay (1985). SEDs plotted in different colours refer to calculations at selected radial resolutions (R/ΔR) – 50, 100, and 200 grid points in radius respectively for x, 2x, and 4x. The black dashed line is the analytical form of the expected optically thin emission in Eq. (22). ν_T is the numerical estimate of the frequency where the SED peaks.