2010/05/31 by Idit Zehavi, Zheng Zheng, David H. Weinberg +14 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/736/1/59
published as Astrophys.J.736:59-88,2011 · 35 pages, 22 figures, updated to match accepted version to ApJ. A version with Figures 1-4 in full resolution is available at http://astronomy.case.edu/izehavi/dr7v2_clustering.pdf
arxiv created 2011/04/18 · arxiv updated 2015/03/16
We measure the luminosity and color dependence of galaxy clustering in the SDSS DR7 main galaxy sample, focusing on the projected correlation function wp(rp) of volume-limited samples. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a Lambda-CDM cosmology. The amplitude of wp(rp) grows slowly with luminosity for L < L_* and increases sharply at higher luminosities, with bias factor b(>L)=1.06+0.23(L/L_*)1.12. At fixed luminosity, redder galaxies have a stronger and steeper wp(rp), a trend that runs steadily from the bluest galaxies to the reddest galaxies. The individual luminosity trends for the red and blue galaxy populations are strikingly different. Blue galaxies show a slow but steady increase of wp(rp) with luminosity, at all scales. The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4L_*, but the lowest luminosity red galaxies (0.04-0.25 L_*) show very strong clustering on scales rp < 2 Mpc/h. Most of the observed trends can be naturally understood within the LCDM+HOD framework. The growth of wp(rp) with luminosity reflects an overall shift in the halo mass scale, in particular an increase in the minimum host halo mass Mmin. The mass at which a halo has, on average, one satellite galaxy brighter than L is M1 ~ 17 Mmin(L) over most of the luminosity range. The growth and steepening of wp(rp) for redder galaxies reflects the increasing fraction of galaxies that are satellite systems in high mass halos instead of central systems in low mass halos, a trend that is especially marked at low luminosities. Our extensive measurements, provided in tabular form, will allow detailed tests of theoretical models of galaxy formation, a firm grounding of semi-empirical models of the galaxy population, and new cosmological tests.