The linear velocity field of SDSS DR7 galaxies: constraints on flow amplitudes and the growth rate

TL;DR

This paper uses SDSS galaxy data to measure large-scale galaxy motions, constraining cosmological parameters like the growth rate and matter power spectrum amplitude, and finds results consistent with the standard $ ext{Lambda}$CDM model.

Contribution

It introduces a novel method to derive bounds on velocity moments and cosmological parameters from galaxy luminosity modulations in SDSS data.

Findings

Results agree with $ ext{Lambda}$CDM predictions

Constraints on velocity moments and $\sigma_8$

Consistency with SDSS photometry zero-point

Abstract

Large-scale peculiar motion modulates the observed luminosity distribution of galaxies. Using about half a million SDSS galaxies, this can be harnessed to obtain bounds on peculiar velocity moments, the amplitude of the linear matter power spectrum, $\sigma_{8}$, and the growth rate of density perturbations at z ~ 0.1. Results obtained from this approach agree well with the predictions of the $\Lambda$CDM model and are consistent with the reported ~ 1% zero-point tilt in the SDSS photometry.