2001/08/31 by Tamon Suwa, T. Suwa, Asao Habe +2
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/368375
published as Astrophys.J. 588 (2003) 7-17 · 30pages, 6figures, Accepted for publication in ApJ
arxiv created 2003/01/09 · openalex publication_date 2003/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We investigate how cluster morphology is affected by the cosmological constant in low-density universes. Using high-resolution cosmological N -body/smoothed particle hydrodynamics simulations of flat cold dark matter (ΛCDM; Ω 0 = 0.3, λ 0 = 0.7) and open cold dark matter (OCDM; Ω 0 = 0.3, λ 0 = 0) universes, we calculate statistical indicators to quantify the irregularity of the cluster morphologies. We study axial ratios, center shifts, cluster clumpiness, and multipole-moment power ratios as indicators for the simulated clusters at z = 0 and 0.5. Some of these indicators are calculated for both the X-ray surface brightness and projected mass distributions. In ΛCDM all these indicators tend to be larger than those in OCDM at z = 0. This result is consistent with the analytical prediction of Richstone, Loeb, & Turner, that is, clusters in ΛCDM are formed later than in OCDM and have more substructure at z = 0. We perform a Kolmogorov-Smirnov test on each indicator for these two models. We then find that the results for the multipole-moment power ratios and the center shifts for the X-ray surface brightness are under the significance level (5%). Our results also show that these two cosmological models can be distinguished more clearly at z = 0 than at z = 0.5 by these indicators.