Simultaneous constraints on bias, normalization and growth index through power spectrum measurements

TL;DR

This paper demonstrates that future redshift surveys can simultaneously constrain galaxy bias, power spectrum normalization, and growth index without external data by measuring the power spectrum at multiple redshifts using a simple growth rate parametrization.

Contribution

It introduces a method to break degeneracies between key cosmological parameters using power spectrum measurements at different redshifts without external priors.

Findings

% precision on  and 5% on 

Bias can be measured to within 1-2% in multiple redshift bins

Method applicable to next-generation surveys like Euclid

Abstract

In this Letter we point out that redshift surveys can break the degeneracy between the galaxy bias, the power spectrum normalization, \sigma_{8,0} and the growth factor, without the need for external information by using a simple and rather general parametrization for the growth rate, the well known \gamma-parametrization and measuring the power spectrum at least at two different redshifts. We find that in next-generation surveys like Euclid, \sigma_{8,0} and \gamma can be measured to within 1% and 5%, respectively, while the bias b(z) can be measured to within 1-2% in each of 14 equal-width redshift bins spanning 0.7<=z<=2.