Rest UV versus Hα line luminosity in LRDs (top) and LBDs (bottom). Broad and narrow components are displayed on the left and right, respectively. Plots are color-coded by the Balmer break strength, defined as f_ν,4230/f_ν,3560. As a reference, the UV-to-Hα luminosity ratios for young starburst galaxies (black dotted line) and typical type 1 AGNs (red solid line) are also shown. The gray shaded band shows the range of the luminosity ratio when the stellar age and gas density are varied for young SFGs.