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GALAXY CLUSTERING IN THE COMPLETED SDSS REDSHIFF SURVEY: THE DEPENDENCE ON COLOR AND LUMINOSITY.
- Source :
- Astrophysical Journal; Jul2011, Vol. 736 Issue 1, Special section p1-30, 30p
- Publication Year :
- 2011
-
Abstract
- We measure the luminosity and color dependence of galaxy clustering in the largest-ever galaxy redshift survey, the main galaxy sample of the Sloan Digital Sky Survey Seventh Data Release. We focus on the projected correlation function w<subscript>p</subscript>(r<subscript>p</subscript>) of volume-limited samples, extracted from the parent sample of ~700,000 galaxies over 8000 deg², extending up to redshift of 0.25. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a ACDM cosmology (inflationary cold dark matter with a cosmological constant). The amplitude of w<subscript>p</subscript> (r<subscript>p</subscript>) grows slowly with luminosity for L < L<subscript>*</subscript> and increases sharply at higher luminosities, with a large-scale bias factor b(>L) x (σ<subscript>8</subscript>/0.8) = 1.06 + 0.21(L/L<subscript>*</subscript>)<superscript>1.12</superscript>, where L is the sample luminosity threshold. At fixed luminosity, redder galaxies exhibit a higher amplitude and steeper correlation function, a steady trend that runs through the "blue cloud" and "green valley" and continues across the "red sequence." The cross-correlation of red and blue galaxies is close to the geometric mean of their autocorrelations, dropping slightly below at r<subscript>p</subscript> < 1 h<superscript>-1</superscript> Mpc. The luminosity trends for the red and blue galaxy populations separately are strikingly different. Blue galaxies show a slow but steady increase of clustering strength with luminosity, with nearly constant shape of w<subscript>p</subscript>(r<subscript>p</subscript>). The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4 L<subscript>*</subscript>, but the lowest luminosity red galaxies (0.044).25 L<subscript>*</subscript>) show very strong clustering on small scales (r<subscript>p</subscript> < 2 h<superscript>-1</superscript> Mpc). Most of the observed trends can be naturally understood within the ACDM+HOD framework. The growth of w<subscript>p</subscript>(r<subscript>p</subscript>) for higher luminosity galaxies reflects an overall shift in the mass scale of their host dark matter halos, in particular an increase in the minimum host halo mass M<subscript>min</subscript>. The mass at which a halo has, on average, one satellite galaxy brighter than L is M<subscript>1</subscript> ≈ 17 M<subscript>min</subscript>(L) over most of the luminosity range, with a smaller ratio above L,. The growth and steepening of w<subscript>p</subscript>(r<subscript>p</subscript>) 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 semiempirical models of the galaxy population, and new constraints on cosmological parameters from combining real-space galaxy clustering with mass-sensitive statistics such as redshift-space distortions, cluster mass-to-light ratios, and galaxy-galaxy lensing. [ABSTRACT FROM AUTHOR]
- Subjects :
- GALAXY clusters
REDSHIFT
ASTRONOMICAL photometry
STAR colors
GALACTIC halos
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X
- Volume :
- 736
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- 67278523
- Full Text :
- https://doi.org/10.1088/0004-637X/736/1/59