October 1, 2025 Dataset Open Access

Data: Nonlinear Matter Power Spectrum from relativistic N-body Simulations: ΛsCDM versus ΛCDM

Akarsu, Özgür; Di Valentino, Eleonora; Vyskocil, Jiri; Yılmaz, Ezgi; Yükselci, A. Emrah; Zhuk, Oleksandr

Matter power spectra presented in the associated paper are obtained from the datasets separately generated from N-body simulations with the relativistic code gevolution [1], and from calculations with the linear Boltzmann code CLASS [2], for matching cosmological best-fit parameters and background cosmologies. Regarding the latter element, we study two cases that are the concordance Lambda-Cold Dark Matter (ΛCDM) model and a late-time modification with a sign-switching vacuum sector (ΛsCDM), and for each model there are two best-fit parameter sets, derived from a Planck-only and a combined "full" dataset. 

P(k) (power spectra) outputs from gevolution are computed at the four redshifts z=15, 2, 1, 0 for the density contrasts of total matter (CDM, baryons, and massive neutrinos) as well as CDM-baryons (cb)-only. A detailed explanation of how the matter sector is handled in simulations is available in the main paper. All runs are carried out in boxes of L=2080 Mpc/h with 0.5 h/Mpc resolution.

Power spectra based on CLASS outputs are obtained from the transfer functions of CDM and baryons, and the respective background densities at z=15, 2, 1, 0. CLASS dataset for the latter is shown only up to z=100.

CDM-baryon P(k) outputs with nonlinear corrections from CLASS implementation of HMcode [3] at z=2,1, and 0 are also included in the published data, and have been used in the plots presented in the Appendix of the related manuscript. 

1. J. Adamek, D. Daverio, R. Durrer, and M. Kunz, gevolution: a cosmological N-body code based on General Relativity, JCAP 07, 053. arXiv:1604.06065 [astro-ph.CO].

2. D. Blas, J. Lesgourgues, and T. Tram, The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes, JCAP 07, 034. arXiv:1104.2933 [astro-ph.CO].

3. A. J. Mead, C. Heymans, L. Lombriser, J. A. Peacock, O. I. Steele, and H. A. Winther, Accurate halo-model matter power spectra with dark energy, massive neutrinos and modified gravitational forces, Mon. Not. Roy. Astron. Soc. 459, 1468 (2016). arXiv:1602.02154 [astro-ph.CO].