Forecasting cosmological parameter constraints from near-future space-based galaxy surveys

TL;DR

Future space-based galaxy surveys will significantly improve constraints on the time evolution of dark energy density, enhancing our understanding of dark energy models beyond current capabilities.

Contribution

This study forecasts the precision of upcoming galaxy surveys in constraining the time dependence of dark energy density using various parameterizations.

Findings

Future surveys can constrain scalar field dark energy density to about 10%

Constraints are nearly ten times better than current data

Improved measurements will refine dark energy model parameters

Abstract

The next generation of space-based galaxy surveys are expected to measure the growth rate of structure to about a percent level over a range of redshifts. The rate of growth of structure as a function of redshift depends on the behaviour of dark energy and so can be used to constrain parameters of dark energy models. In this work we investigate how well these future data will be able to constrain the time dependence of the dark energy density. We consider parameterizations of the dark energy equation of state, such as XCDM and wCDM, as well as a consistent physical model of time-evolving scalar field dark energy, \phi CDM. We show that if the standard, specially-flat cosmological model is taken as a fiducial model of the Universe, these near-future measurements of structure growth will be able to constrain the time-dependence of scalar field dark energy density to a precision of about 10%, which is almost an order of magnitude better than what can be achieved from a compilation of currently available data sets.