Rest-frame g − r color–mass diagram for early-type galaxies from simulation. The squares indicate median values, and the error bar of each square is 1σ of the median values from 200 bootstrap resampling. The green line divides galaxies into red and blue populations as in Bluck et al. (2014). The color distribution of the simulated sample shows a tail extended to blue color in comparison with that of the observational sample. However, the color distribution of the simulated sample is similar to that of the observational sample in the sense that most of the galaxies are above the green line, and their median color values are very similar (0.7–0.8) across the whole mass range without environmental dependence.