Observed radio continuum SEDs at three frequencies: 1.5, 3, and 6 GHz for three sources in our sample. The error bars represent 1σ errors on the flux measurement. The gray line in each panel is an overlay (not a fit) for a simple radio-SED (Eq. (1)) normalized to the 3 GHz observed flux density with f_th = 0.1 at 1 GHz and α_nth = −0.8 commonly seen in star-forming galaxies. The left panel shows an example of a radio-SED which is close to the standard radio-SED (Eq. (1)). The middle panel shows an example that has a steep spectrum above 3 GHz and is close to the standard radio-SED below 3 GHz. The right panel shows the case of a broken SED.