Mass-metallicity relation from z=5 to the present: Evidence for a
  transition in the mode of galaxy growth at z=2.6 due to the end of sustained
  primordial gas infall
  We analyze the redshift evolution of the mass-metallicity relation in a
sample of 110 Damped Ly$\alpha$ absorbers spanning the redshift range
$z=0.11-5.06$ and find that the zero-point of the correlation changes
significantly with redshift. The evolution is such that the zero-point is
constant at the early phases of galaxy growth (i.e. no evolution) but then
features a sharp break at $z=2.6\pm 0.2$ with a rapid incline towards lower
redshifts such that damped absorbers of identical masses are more metal rich at
later times than earlier. The slope of this mass metallicity correlation
evolution is $0.35 \pm 0.07$ dex per unit redshift.
  We compare this result to similar studies of the redshift evolution of
emission selected galaxy samples and find a remarkable agreement with the slope
of the evolution of galaxies of stellar mass log$(M_{*}/M_\odot) \approx 8.5$.
This allows us to form an observational tie between damped absorbers and
galaxies seen in emission.
  We use results from simulations to infer the virial mass of the dark matter
halo of a typical DLA galaxy and find a ratio $(M_{vir}/M_{*}) \approx 30$.
  We compare our results to those of several other studies that have reported
strong transition-like events at redshifts around $z=2.5-2.6$ and argue that
all those observations can be understood as the consequence of a transition
from a situation where galaxies were fed more unprocessed infalling gas than
they could easily consume to one where they suddenly become infall starved and
turn to mainly processing, or re-processing, of previously acquired gas.
