Cosmological constraints from a combination of galaxy clustering and lensing - III. Application to SDSS data

• Published in: Monthly notices of the Royal Astronomical Society Vol. 430; no. 2; pp. 767 - 786
• Main Authors: Cacciato, Marcello, van den Bosch, Frank C., More, Surhud, Mo, Houjun, Yang, Xiaohu
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01-04-2013
• Subjects: Anisotropy; Bias; Dark matter; Luminosity; Measurement; Star & galaxy formation; methods: statistical; gravitational lensing: weak; cosmological parameters; dark matter; large-scale structure of Universe; galaxies: haloes
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/sts525

We simultaneously constrain cosmology and galaxy bias using measurements of galaxy abundances, galaxy clustering and galaxy-galaxy lensing taken from the Sloan Digital Sky Survey. We use the conditional luminosity function (which describes the halo occupation statistics as a function of galaxy luminosity) combined with the halo model (which describes the non-linear matter field in terms of its halo building blocks) to describe the galaxy-dark matter connection. We explicitly account for residual redshift-space distortions in the projected galaxy-galaxy correlation functions, and marginalize over uncertainties in the scale dependence of the halo bias and the detailed structure of dark matter haloes. Under the assumption of a spatially flat, vanilla Λ cold dark matter (ΛCDM) cosmology, we focus on constraining the matter density, Ωm, and the normalization of the matter power spectrum, σ8, and we adopt 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) priors for the spectral index, n, the Hubble parameter, h, and the baryon density, Ωb. We obtain that Ωm = 0.278+ 0.023
− 0.026 and σ8 = 0.763+ 0.064
− 0.049 (95 per cent CL). These results are robust to uncertainties in the radial number density distribution of satellite galaxies, while allowing for non-Poisson satellite occupation distributions results in a slightly lower value for σ8 (0.744+ 0.056
− 0.047). These constraints are in excellent agreement (at the 1σ level) with the cosmic microwave background constraints from WMAP. This demonstrates that the use of a realistic and accurate model for galaxy bias, down to the smallest non-linear scales currently observed in galaxy surveys, leads to results perfectly consistent with the vanilla ΛCDM cosmology.