## Abstract

The next generation mass probes will obtain information on non-linear power spectra P(k, z) and their evolution, allowing us to investigate the nature of Dark Energy. To exploit such data we need high-precision simulations, extending at least up to scales of k≃ 10hMpc^{-1}, where the effects of baryons can no longer be neglected. In this paper, we present a series of large scale hydrodynamical simulations for ΛCDM and dynamical Dark Energy (dDE) models, in which the equation of state parameter is z dependent. The simulations include gas cooling, star formation and Supernovae feedback. They closely approximate the observed star formation rate and the observationally derived star/Dark Matter mass ratio in collapsed systems. Baryon dynamics cause spectral shifts exceeding 1 per cent at k > 2-3hMpc^{-1} compared to pure N-body simulations in the ΛCDM simulations. This agrees with previous studies, although we find a smaller effect (∼50 per cent) on the power spectrum amplitude at higher k values. dDE exhibits similar behaviour, even though the dDE simulations produce ∼20 per cent less stars than the analogous ΛCDM cosmologies. Finally, we show that the technique introduced in Casarini et al. to obtain spectra for any w(z) cosmology from constant-w models at any redshift still holds when gas physics is taken into account. While this relieves the need to explore the entire functional space of DE state equations, we illustrate a severe risk that future data analysis could lead to misinterpretation of the DE state equation.

Original language | English (US) |
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Pages (from-to) | 911-920 |

Number of pages | 10 |

Journal | Monthly Notices of the Royal Astronomical Society |

Volume | 412 |

Issue number | 2 |

DOIs | |

State | Published - Apr 2011 |

## Keywords

- Cosmology: dark energy
- Cosmology: dark matter
- Cosmology: theory
- Galaxies: haloes
- Large-scale structure of Universe
- Methods: numerical

## ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science