Characterizing the satellites of massive galaxies up to z~2: young
  populations to build the outskirts of nearby massive galaxies
  The accretion of minor satellites is currently proposed as the most likely
mechanism to explain the significant size evolution of the massive galaxies
during the last ~10 Gyr. In this paper we investigate the rest-frame colors and
the average stellar ages of satellites found around massive galaxies (Mstar
10^11Msun) since z~2. We find that the satellites have bluer colors than their
central galaxies. When exploring the stellar ages of the galaxies, we find that
the satellites have similar ages to the massive galaxies that host them at high
redshifts, while at lower redshifts they are, on average, ~1.5 Gyr younger. If
our satellite galaxies create the envelope of nearby massive galaxies, our
results would be compatible with the idea that the outskirts of those galaxies
are slightly younger, metal-poorer and with lower [alpha/Fe] abundance ratios
than their inner regions.
