Redshift evolution of the dynamical properties of massive galaxies from
  SDSS-III/BOSS
  We study the redshift evolution of the dynamical properties of ~180,000
massive galaxies from SDSS-III/BOSS combined with a local early-type galaxy
sample from SDSS-II in the redshift range 0.1<z< 0.6. The typical stellar mass
of this sample is Mstar~2x10^{11} Msun. We analyze the evolution of the galaxy
parameters effective radius, stellar velocity dispersion, and the dynamical to
stellar mass ratio with redshift. As the effective radii of BOSS galaxies at
these redshifts are not well resolved in the SDSS imaging we calibrate the SDSS
size measurements with HST/COSMOS photometry for a sub-sample of galaxies. We
further apply a correction for progenitor bias to build a sample which consists
of a coeval, passively evolving population. Systematic errors due to size
correction and the calculation of dynamical mass, are assessed through Monte
Carlo simulations. At fixed stellar or dynamical mass, we find moderate
evolution in galaxy size and stellar velocity dispersion, in agreement with
previous studies. We show that this results in a decrease of the dynamical to
stellar mass ratio with redshift at >2sigma significance. By combining our
sample with high-redshift literature data we find that this evolution of the
dynamical to stellar mass ratio continues beyond z~0.7 up to z>2 as Mdyn/Mstar~
(1+z)^{-0.30+/- 0.12} further strengthening the evidence for an increase of
Mdyn/Mstar with cosmic time. This result is in line with recent predictions
from galaxy formation simulations based on minor merger driven mass growth, in
which the dark matter fraction within the half-light radius increases with
cosmic time.
