At a given M_⋆, galaxies with a higher Σ₁ are redder. We plot Σ₁ vs. M_⋆, color coded by the rest-frame (B − I) color for the ZENS galaxies. The filled and empty large circles show the QGs above and below the mass completeness limit; the small dots indicate star-forming galaxies. The black and gray dashed lines show the best-fit ﹩{{\rm{\Sigma }}}_{1}\mbox{--}{M}_{\star }﹩ relation for the QGs, i.e., Σ₁ ridgeline, obtained respectively from our data (Equation (1)) and by Fang et al. (2013) on their SDSS sample. The error bars in the bottom right corner show the average 1σ uncertainties; the gray shaded area marks the unphysical region of parameter space where ﹩{{\rm{\Sigma }}}_{1}\gt {M}_{\star }/\pi ﹩. At a given M_⋆, QGs with higher Σ₁ have typically redder (B − I) colors than QGs with lower Σ₁.