Clustering of luminous red galaxies I: large scale redshift space distortions

Anna Cabre; Enrique Gaztanaga

doi:10.1111/j.1365-2966.2008.14281.x

paper

Clustering of luminous red galaxies I: large scale redshift space distortions

arXiv:0807.2460 · doi:10.1111/j.1365-2966.2008.14281.x

Abstract

This is the first paper of a series where we study the clustering of LRG galaxies in the latest spectroscopic SDSS data release, DR6, which has 75000 LRG galaxies covering over 1 $Gp c^{3} / h^{3}$ at $0.15 < z < 0.47$ . Here we focus on modeling redshift space distortions in $\xips$, the 2-point correlation in separate line-of-sight and perpendicular directions, on large scales. % and away from the line-of-sight. We use large mock simulations to study the validity of models and errors. We show that errors in the data are dominated by a shot-noise term that is 40% larger than the Poisson error commonly used. We first use the normalized quadrupole for the whole sample (mean z=0.34) to estimate $β = f (Ω_{m}) / b = 0.34 \pm 0.03$ , where $f (Ω_{m})$ is the linear velocity growth factor and $b$ is the linear bias parameter that relates galaxy to matter fluctuations on large scales. We next use the full $\xips$ plane to find $Ω_{0 m} = 0.245 \pm 0.020$ (h=0.72) and the biased amplitude $b σ_{8} = 1.56 \pm 0.09$ . For standard gravity, we can combine these measurements to break degeneracies and find $σ_{8} = 0.85 \pm 0.06$ , $b = 1.85 \pm 0.25$ and $f (Ω_{m}) = 0.64 \pm 0.09$ . We present constraints for modified theories of gravity and find that standard gravity is consistent with data as long as $0.80 < σ_{8} < 0.92$ . We also calculate the cross-correlation with WMAP5 and show how both methods to measure the growth history are complementary to constrain non-standard models of gravity. Finally, we show results for different redshift slices, including a prominent BAO peak in the monopole at different redshifts. (Abridged)

arXiv comment31 pages, 65 figures

Clustering of luminous red galaxies I: large scale redshift space distortions

Abstract

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