A new model for the full shape of the large-scale power spectrum

TL;DR

This paper introduces a new model based on renormalized perturbation theory that accurately describes the full shape of the large-scale power spectrum, accounting for non-linear effects, and improves constraints on dark energy parameters.

Contribution

The paper presents a novel, simple model for the full shape of the large-scale power spectrum that outperforms previous models in accuracy and utility for cosmological parameter estimation.

Findings

Model accurately describes power spectrum for k < 0.15 h/Mpc

Provides tighter constraints on dark energy equation of state

Comparable to full-shape correlation function analyses

Abstract

We present a new model for the full shape of large-scale the power spectrum based on renormalized perturbation theory. To test the validity of this prescription, we compare this model against power spectra measured in a suite of 50 large volume, moderate resolution N-body simulations. Our results indicate that this simple model provides an accurate description of the full shape of the power spectrum taking into account the effects of non-linear evolution, redshift-space distortions and halo bias for scales k < 0.15 h/Mpc, making it a valuable tool for the analysis of forthcoming galaxy surveys. Even though its application is restricted to large scales, this prescription can provide tighter constraints on the dark energy equation of state parameter w_{DE} than those obtained by modelling the baryonic acoustic oscillations signal only, where the information of the broad-band shape of the power spectrum is discarded. Our model is able to provide constraints comparable to those obtained by applying a similar model to the full shape of the correlation function, which is affected by different systematics. Hence, with accurate modelling of the power spectrum, the same cosmological information can be extracted from both statistics.