Mapping the Real Space Distributions of Galaxies in SDSS DR7: II. Measuring the growth rate, clustering amplitude of matter and biases of galaxies at redshift $0.1$

TL;DR

This paper extends a real-space mapping method to flux-limited galaxy samples, enabling accurate measurements of galaxy clustering, biases, and the growth rate of structure from SDSS data, with implications for cosmological parameters.

Contribution

It introduces an improved real-space mapping technique applicable to flux-limited samples and demonstrates its effectiveness using SDSS DR7 data for cosmological measurements.

Findings

Accurate recovery of real-space correlation functions and galaxy biases.

Unbiased estimate of growth rate $f\sigma_8$ with ~10% accuracy.

Constraints on $f$, $\sigma_8$, and galaxy bias at $z=0.1$.

Abstract

We extend the real-space mapping method developed in Shi et at. (2016) so that it can be applied to flux-limited galaxy samples. We use an ensemble of mock catalogs to demonstrate the reliability of this extension, showing that it allows for an accurate recovery of the real-space correlation functions and galaxy biases. We also demonstrate that, using an iterative method applied to intermediate-scale clustering data, we can obtain an unbiased estimate of the growth rate of structure $f\sigma_8$, which is related to the clustering amplitude of matter, to an accuracy of $\sim 10\%$. Applying this method to the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7), we construct a real-space galaxy catalog spanning the redshift range $0.01 \leq z \leq 0.2$, which contains 584,473 galaxies in the north Galactic cap (NGC). Using this data, we infer $\fss$ at a median redshift $z=0.1$, which is consistent with the WMAP9 cosmology at the $1\sigma$ level. By combining this measurement with the real-space clustering of galaxies and with galaxy-galaxy weak lensing measurements for the same sets of galaxies, we are able to break the degeneracy between $f$, $\sigma_8$, and $b$. From the SDSS DR7 data alone, we obtain the following cosmological constraints at redshift $z=0.1$: $f=$$0.464^{+0.040}_{-0.040}$, $\sigma_8=0.769^{+0.121}_{-0.089}$, and $b=1.910^{+0.234}_{-0.268}$, $1.449^{+0.194}_{-0.196}$, $1.301^{+0.170}_{-0.177}$, and $1.196^{+0.159}_{-0.161}~$ for galaxies within different absolute magnitude bins $^{0.1}{\rm M}_r-5\log h=[-23,0, -22.0], [-22,0, -21.0], [-21.0, -20.0]$ and $[-20.0, -19.0]$, respectively.