2003/09/30 by Ewa L. Łokas, Ewa L. Lokas, Paul Bode +1 · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.07529.x
published as Mon.Not.Roy.Astron.Soc. 349 (2004) 595 · 9 pages, 6 figures, revised version (with minor changes) accepted by MNRAS
arxiv created 2003/12/11 · openalex publication_date 2004/04/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We use N-body simulations to measure mass functions in flat cosmological models with quintessence characterized by constant w with w =−1, −2/3 and −1/2. The results are compared with the predictions of the formula proposed by Jenkins et al. at different redshifts, in terms of friends-of-friends (FOF) masses as well as Abell masses appropriate for direct comparison with observations. The formula reproduces quite well the mass functions of simulated haloes in models with quintessence. We use the cluster mass function data at a number of redshifts from Carlberg et al. to constrain Ω0, σ8 and w. The best fit is obtained in the limit w→ 0, but none of the values of w in the considered range −1 ≤w < 0 can actually be excluded. However, the adopted value of w significantly affects the constraints in the Ω0–σ8 plane. Taking into account the dependence on w we find Ω0 = 0.32 ± 0.15 and σ8 = 0.85+0.38−0.12 (68 per cent confidence level). Because less negative w push the confidence regions toward higher Ω0 and lower σ8, we conclude that relaxing the assumption of w =−1, typically made in such comparisons, may resolve the discrepancy between recent cluster mass function results (yielding rather low Ω0 and high σ8) and most other estimates. The fact that high w values are preferred may, however, also point towards some unknown systematics in the data or the model with constant w being inadequate.