On Sizes, Kinematics, M/L Gradients, and Light Profiles of Massive
  Compact Galaxies at z~2
  We present a detailed analysis of the structure and resolved stellar
populations of simulated merger remnants, and compare them to observations of
compact quiescent galaxies at z ~ 2. We find that major merging is a viable
mechanism to produce systems of ~ 10^11 Msun and ~ 1 kpc size, provided the gas
fraction at the time of final coalescence is high (~ 40%), and provided that
the progenitors are compact star-forming galaxies, as expected at high
redshift. Their integrated spectral energy distributions and velocity
dispersions are in good agreement with the observations, and their position in
the (v_{maj}/sigma, ellipticity) diagram traces the upper envelope of the
distribution of lower redshift early-type galaxies. The simulated merger
remnants show time- and sightline-dependent M/L ratio gradients that result
from a superposition of radially dependent stellar age, stellar metallicity,
and extinction. The median ratio of effective radius in rest-frame V-band light
to that in mass surface density is ~ 2 during the quiescent remnant phase. This
is typically expressed by a negative color gradient (i.e., red core), which we
expect to correlate with the integrated color of the system. Finally, the
simulations differ from the observations in their surface brightness profile
shape. The simulated remnants are typically best fit by high (n >> 4) Sersic
indices, whereas observed quiescent galaxies at z ~ 2 tend to be less cuspy
(median n ~ 2.3). Limiting early star formation in the progenitors may be
required to prevent the simulated merger remnants from having extended wings.
