Understanding the nature of luminous red galaxies (LRGs): Connecting
  LRGs to central and satellite subhalos
  We develop a novel abundance matching method to construct a mock catalog of
luminous red galaxies (LRGs) in SDSS, using catalogs of halos and subhalos in
N-body simulations for a LCDM model. Motivated by observations suggesting that
LRGs are passively-evolving, massive early-type galaxies with a typical age
>5Gyr, we assume that simulated halos at z=2 (z2-halo) are progenitors for
LRG-host subhalos observed today, and we label the most tightly bound particles
in each progenitor z2-halo as LRG ``stars''. We then identify the subhalos
containing these stars to z=0.3 (SDSS redshift) in descending order of the
masses of z2-halos until the comoving number density of the matched subhalos
becomes comparable to the measured number density of SDSS LRGs, n=10^{-4}
(h/Mpc)^3. Once the above prescription is determined, our only free parameter
is the number density of halos identified at z=2 and this parameter is fixed to
match the observed number density at z = 0.3. By tracing subsequent merging and
assembly histories of each progenitor z2-halo, we can directly compute, from
the mock catalog, the distributions of central and satellite LRGs and their
internal motions in each host halo at z=0.3. While the SDSS LRGs are galaxies
selected by the magnitude and color cuts from the SDSS images and are not
necessarily a stellar-mass-selected sample, our mock catalog reproduces a host
of SDSS measurements: the halo occupation distribution for central and
satellite LRGs, the projected auto-correlation function of LRGs, the
cross-correlation of LRGs with shapes of background galaxies (LRG-galaxy weak
lensing), and the nonlinear redshift-space distortion effect, the Finger-of-God
effect, in the angle-averaged redshift-space power spectrum.
