Stellar mass as a function of stellar scalelength. The symbols “+” and “Δ” show the MIRAGE galaxy mergers and isolated disks, respectively. The color encodes the time evolution since the initial conditions. Black symbols display the MASSIV data, according to measurements found in Vergani et al. (2012) and Epinat et al. (2012). The stellar mass–size relation derived in Dutton et al. (2011) and shifted to z = 1.5 is overplotted with the red solid curve. The dotted curves show the dispersion computed for z = 1.5 from the relation derived in Dutton et al. (2011). We also display the mass–size relation for z = 0.5 (green line) and z = 2.5 (orange line) to emphasize the redshift evolution of the relation.