Shogo Masaki, Chiaki Hikage, Masahiro Takada, David N. Spergel, Naoshi Sugiyama
We develop a novel abundance matching method to construct a mock catalog of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogs of halos and subhalos in N-body simulations for a Lambda-dominated, cold dark matter 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, 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_LRG=10^{-4} (h/Mpc)^3. 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 $N$-body simulations, 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.
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http://arxiv.org/abs/1211.7077
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