http://arxiv.org/abs/1812.05594
We present a general method to compute the nonlinear matter power spectrum for dark energy and modified gravity scenarios with per-cent-level accuracy. By adopting the halo model and nonlinear perturbation theory, we predict the reaction of a $\Lambda$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 $k \approx 1 \, h \, {\rm Mpc}^{-1}$. 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 $\Lambda$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.
M. Cataneo, L. Lombriser, C. Heymans, et. al.
Fri, 14 Dec 18
8/58
Comments: 18+6 pages, 15 figures, submitted to MNRAS