Effects of dark energy anisotropic stress on the matter power spectrum

2020/04/30 by Gabriela Garcia-Arroyo, Jorge L. Cervantes–Cota, Jorge L. Cervantes-Cota +3 · 5 citations
Physics and Astronomy · #Amplitude #Anisotropy #Astrophysics #Black Holes and Theoretical Physics #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Dark energy #Dark matter #Galaxies: Formation, Evolution, Phenomena #Lambda #Mathematical physics #Matter power spectrum #Physics #Planck #Quadrupole #Quantum electrodynamics #Quantum mechanics #Redshift #Spectral density #Statistics #astro-ph.CO #gr-qc

paper · pdf · doi:10.1016/j.dark.2020.100668

published in Physics of the Dark Universe 30, 100668 (Elsevier BV) · 19 pages, 13 figures, 1 table

openalex publication_date 2020/07/03 · arxiv created 2020/07/08 · arxiv updated 2020/07/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We study the effects of dark energy (DE) anisotropic stress on features of the matter power spectrum (PS). We employ the Parametrized Post-Friedmannian (PPF) formalism to emulate an effective DE, and model its anisotropic stress properties through a two-parameter equation that governs its overall amplitude (g₀) and transition scale (c_g). For the background cosmology, we consider different equations of state to model DE including a constant w₀ parameter, and models that provide thawing (CPL) and freezing (nCPL) behaviors. We first constrain these parameters by using the Pantheon, BAO, H₀ and CMB Planck data. Then, we analyze the role played by these parameters in the linear PS. In order for the anisotropic stress not to provoke deviations larger than 10% and 5% with respect to the ΛCDM PS at k ∼ 0.01 h/Mpc, the parameters have to be in the range -0.30< g₀ < 0.32, 0 ≤ c_g² < 0.01 and -0.15 < g₀ < 0.16, 0 ≤ c_g² < 0.01, respectively. Additionally, we compute the leading nonlinear corrections to the PS using standard perturbation theory in real and redshift space, showing that the differences with respect to the ΛCDM are enhanced, especially for the quadrupole and hexadecapole RSD multipoles.

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