Size/mass evolution of G1 (solid line) and G2 (dashed line) as a function of redshift. We show the evolution of R₂₀₀ (upper-left panels), the total mass (M₂₀₀, lower-left panels), the gas mass (M_gas, upper-right panels) and the stellar mass (M_star, lower-right panels), all within R₂₀₀. For G1, the peak seen in all panels at z ≈ 0.65 is owing to the emergence of two large objects within R₂₀₀ (see further discussion in Sect. 4).