Number density distribution from the different functions in Eq. (11) at z = 1. The solid line is the stellar mass function (Φ) multiplied by the major merger rate (R_MM). The dashed line includes the major merger efficiency function (E_MM). The dotted line includes the fraction of late-type galaxies (f_LTG) and provides the final function that we integrate over stellar mass and cosmic time to obtain ρ_wet. The vertical dashed line marks the limiting stellar mass that define massive galaxies, M_{⋆, lim} = 10^11.25  M_⊙, while the dotted lines mark the stellar masses M _⋆ ,1 = 10^10.15  M_⊙ and M _⋆ ,2 = 10^11.05  M_⊙ when f_sf = 0 (see text for details). (A colour version of this plot is available at the electronic edition.)