Cosmic degeneracies III: N-body simulations of interacting dark energy with non-Gaussian initial conditions

2018/06/30 by Mahmoud Hashim, M. Hashim, C. Giocoli +6
Physics and Astronomy · #Astrophysics #COSMIC cancer database #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dark matter #Dark matter halo #Degeneracy (biology) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gaussian #Halo #Halo effect #Halo mass function #Matter power spectrum #Physics #Quantum mechanics #Spectral density #Statistics #Structure formation #Void (composites) #astro-ph.CO

paper · pdf · doi:10.1093/mnras/sty2450

published as Mon. Not. Roy. Astron. Soc. 481 (2018) 2933 · 14 pages, 9 figures, Version accepted by MNRAS

openalex created_date 2018/06/13 · arxiv created 2018/09/06 · openalex publication_date 2018/09/06 · arxiv updated 2018/10/22 · openalex updated_date 2026/08/05

Abstract

We perform for the first time N-body simulations of interacting dark energy assuming non-Gaussian initial conditions, with the aim of investigating possible degeneracies of these two theoretically independent phenomena in different observational probes. We focus on the large-scale matter distribution, as well as on the statistical and structural properties of collapsed haloes and cosmic voids. On very large scales, we show that it is possible to choose the interaction and non-Gaussian parameters such that their effects on the halo power spectrum cancel, and the power spectrum is indistinguishable from a Λ cold dark matter (⁠|Λ \rm CDM|⁠) model. On small scales, measurements of the non-linear matter power spectrum, halo-matter bias, halo and subhalo mass function, and cosmic void number function validate the degeneracy determined on large scales. However, the internal structural properties of haloes and cosmic voids, namely halo concentration–mass relation and void density profile, are very different from those measured in the |Λ \rm CDM| model, thereby breaking the degeneracy. In practice, the values of fNL required to cancel the effect of interaction are already ruled by observations. Our results show in principle that the combination of large- and small-scale probes is needed to constrain interacting dark energy and primordial non-Gaussianity separately.

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