Phase space diagram of galaxies in two dark matter halos with M_vir > 10¹³ M_⊙ at z = 1. The black dashed line is the escape velocity curve profile of the more massive halos. Galaxies with M_* > 10⁹ M_⊙ are classified into two groups, either they are star-forming (b > 0.1) or quenched (b < 0.1). See the texts for the definition of the parameter b. Their 0.5σ and 1σ distributions are displayed with the contours with dashed line and solid line, respectively. Even at a high redshift of z = 1, a clear separation between the distributions of star-forming and quenched galaxies is seen.