Matter power spectra in modified gravity: a comparative study of approximations and N -body simulations

Journal Article · 17 November 2024 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stae2562 · OSTI ID:2480956

Bose, B. ; Gupta, A. Sen; Fiorini, B.; Brando, G.; Hassani, F.; Baker, T.; Lombriser, L.; Li, B. ; Ruan, C.; Hernández-Aguayo, C. ; Atayde, L.; Frusciante, N.

ABSTRACT Testing gravity and the concordance model of cosmology, $$\Lambda$$CDM, at large scales is a key goal of this decade’s largest galaxy surveys. Here we present a comparative study of dark matter power spectrum predictions from different numerical codes in the context of three popular theories of gravity that induce scale-independent modifications to the linear growth of structure: nDGP, Cubic Galileon, and K-mouflage. In particular, we compare the predictions from N-body simulations solving the full scalar field equation, two N-body codes with approximate time integration schemes, a parametrized modified N-body implementation, and the analytic halo model reaction approach. We find the modification to the $$\Lambda$$CDM spectrum is in 2 per cent agreement at $$z\le 1$$ and $$k\le 1~h\,{\rm Mpc}^{-1}$$ over all gravitational models and codes, in accordance with many previous studies, indicating these modelling approaches are robust enough to be used in forthcoming survey analyses under appropriate scale cuts. We further make public the new code implementations presented, specifically the halo model reaction K-mouflage implementation and the relativistic Cubic Galileon implementation.

• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain
• OSTI ID: 2480956
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 1 Vol. 536; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English