Testing Standard Cosmology with Large Scale Structure

TL;DR

This paper evaluates the potential of BigBOSS and JDEM-PS experiments to test the standard cosmological model and general relativity by measuring the gravitational growth index and other parameters through large-scale structure observations.

Contribution

It provides forecasts for how well these experiments can constrain cosmological parameters, including the gravitational growth index, considering various observational and modeling uncertainties.

Findings

BigBOSS can measure b3 with an uncertainty of 0.043.

JDEM-PS can measure b3 with an uncertainty of 0.054.

Including priors reduces uncertainties to 0.031 and 0.038, respectively.

Abstract

The galaxy power spectrum contains information on the growth of structure, the growth rate through redshift space distortions, and the cosmic expansion through baryon acoustic oscillation features. We study the ability of two proposed experiments, BigBOSS and JDEM-PS, to test the cosmological model and general relativity. We quantify the latter result in terms of the gravitational growth index \gamma, whose value in general relativity is \gamma\approx 0.55. Significant deviations from this value could indicate new physics beyond the standard model of cosmology. The results show that BigBOSS (JDEM-PS) would be capable of measuring \gamma with an uncertainty \sigma(\gamma) = 0.043 (0.054), which tightens to \sigma(\gamma) = 0.031 (0.038) if we include Stage III data priors, marginalizing over neutrino mass, time varying dark energy equation of state, and other parameters. For all dark energy parameters and related figures of merit the two experiments give comparable results. We also carry out some studies of the influence of redshift range, resolution, treatment of nonlinearities, and bias evolution to enable further improvement.