On the road to percent accuracy: nonlinear reaction of the matter power spectrum to dark energy and modified gravity

Matteo Cataneo; Lucas Lombriser; Catherine Heymans; Alexander Mead; Alexandre Barreira; Sownak Bose; Baojiu Li

doi:10.1093/mnras/stz1836

paper

On the road to percent accuracy: nonlinear reaction of the matter power spectrum to dark energy and modified gravity

arXiv:1812.05594 · doi:10.1093/mnras/stz1836

Abstract

We present a general method to compute the nonlinear matter power spectrum for dark energy and modified gravity scenarios with percent-level accuracy. By adopting the halo model and nonlinear perturbation theory, we predict the reaction of a $Λ$ CDM matter power spectrum to the physics of an extended cosmological parameter space. By comparing our predictions to $N$ -body simulations we demonstrate that with no-free parameters we can recover the nonlinear matter power spectrum for a wide range of different $w_{0}$ - $w_{a}$ dark energy models to better than 1% accuracy out to $k \approx 1 h Mpc^{- 1}$ . We obtain a similar performance for both DGP and $f (R)$ gravity, with the nonlinear matter power spectrum predicted to better than 3% accuracy over the same range of scales. When including direct measurements of the halo mass function from the simulations, this accuracy improves to 1%. With a single suite of standard $Λ$ CDM $N$ -body simulations, our methodology provides a direct route to constrain a wide range of non-standard extensions to the concordance cosmology in the high signal-to-noise nonlinear regime.

arXiv comment18+6 pages, 15 figures. Matches MNRAS accepted version. Few typos corrected

On the road to percent accuracy: nonlinear reaction of the matter power spectrum to dark energy and modified gravity

Abstract

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