Measuring the matter energy density and Hubble parameter from Large Scale Structure

TL;DR

This paper proposes a method to directly measure the matter density and Hubble parameter from large scale structure data, requiring high-redshift growth rate measurements to achieve precise cosmological constraints.

Contribution

It introduces a novel approach to determine matter density and Hubble parameter evolution without prior assumptions, utilizing high-redshift growth rate data from upcoming galaxy surveys.

Findings

Achieves <3% error in matter density at z > 3.5

Can estimate H(z) evolution with <5% error at z ≤ 1.2

Insensitive to errors in normalized growth rate measurements

Abstract

We investigate the method to measure both the present value of the matter energy density contrast and the Hubble parameter directly from the measurement of the linear growth rate which is obtained from the large scale structure of the Universe. From this method, one can obtain the value of the nuisance cosmological parameter $\Omo$ (the present value of the matter energy density contrast) within 3% error if the growth rate measurement can be reached $z > 3.5$. One can also investigate the evolution of the Hubble parameter without any prior on the value of $H_0$ (the current value of the Hubble parameter). Especially, estimating the Hubble parameter are insensitive to the errors on the measurement of the normalized growth rate $f \sigma_8$. However, this method requires the high $z$ ($z > 3.5$) measurement of the growth rate in order to get the less than 5% errors on the measurements of $H(z)$ at $z \leq 1.2$ with the redshift bin $\Delta z = 0.2$. Thus, this will be suitable for the next generation large scale structure galaxy surveys like WFMOS and LSST.