The growth of massive galaxies since z=2

From van Dokkum et al. (http://arxiv.org/abs/0912.0514).

The first figure shows the average radial surface density profiles for massive galaxies in five redshift bins (z=2, 1.6, 1.1, 0.6, 0 from bottom to top). The profiles come from stacking galaxies from the NEWFIRM Medium-Band Survey.

The second figure shows how much of the mass growth for these galaxies over 0<z<2 comes from star formation, and from mergers (the growth in mergers is just inferred to be the observed change in stellar mass minus the change in stellar mass that is estimated from the star formation rates)