Radio brightness spectra for star formation powered radio emission based on the mixed synchrotron/thermal model of Condon et al. (1991) (see Eq. (1)) assuming a 10% free-free emission contribution at 1.4 GHz. Successive curves correspond to increasing the frequency at which the free-free optical depth is τ = 1 which, using Eq. (3), translates to successive curves of star formation rate density: 10^-3, 10^-2, 10^-1, 10⁰, 10¹, 10², 10³, 10⁴, and 10⁵ [ M_⊙ yr^-1 kpc^-2 ]. The average surface brightness of the resolved features A, B, C, D, E, and H detected at 5.0 GHz in Fig. 2 is marked with a star. The highest peak surface brightness (A = 2970 mJy/arcsec²) is plotted as the upper limit, and the lowest peak surface brightness (E = 980 mJy/arcsec²) is plotted as the lower limit.