On the road to percent accuracy: non-linear reaction of the matter power spectrum to dark energy and modified gravity
Abstract
We present a general method to compute the non-linear matter power spectrum for dark energy (DE) and modified gravity scenarios with per cent-level accuracy. By adopting the halo model and non-linear perturbation theory, we predict the reaction of a lambda cold dark matter (ΛCDM) 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 non-linear matter power spectrum for a wide range of different w0-wa DE models to better than 1 per cent accuracy out to k ≈ 1 h Mpc^{-1}. We obtain a similar performance for both DGP and f(R) gravity, with the non-linear matter power spectrum predicted to better than 3 per cent accuracy over the same range of scales. When including direct measurements of the halo mass function from the simulations, this accuracy improves to 1 per cent. With a single suite of standard ΛCDM 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 non-linear regime.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2019
- DOI:
- 10.1093/mnras/stz1836
- arXiv:
- arXiv:1812.05594
- Bibcode:
- 2019MNRAS.488.2121C
- Keywords:
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- methods: analytical;
- large-scale structure of Universe;
- cosmology: theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 18+6 pages, 15 figures. Matches MNRAS accepted version. Few typos corrected