3 GHz radio fluxes (or 3σ limits) of TOUGH galaxies from the VLA (yellow data points), compared to measured or predicted radio fluxes from galaxies inside GOODS-N (gray circles). To calculate the fluxes of the field galaxies, we use the reduced VLA map of this field presented by Morrison et al. (2010) to directly match against the galaxy catalog of Kajisawa et al. (2011), scaling the 1.4 GHz flux density from that survey to 3 GHz using an average spectral index of α = 0.75. For sources that are not detected, we calculate the predicted radio flux density based on the star formation rate estimates in Kajisawa et al. (2011). Galaxies with hard X-ray detections are excluded (open circles). We also evaluate the fraction of cosmic star formation occurring in detected radio galaxies using this method by directly summing the star formation rates of all galaxies above and below 10 μJy (see text for details). The solid lines show a linear fit to the redshift-dependent 50th and 88th percentiles. We also show the limits resulting from stacks of our nondetections at 0.5  <  z  <  1.0 and 2.0  <  z  <  2.5.