The cosmic web for density perturbations of various scales

¹ Tartu Observatory, 61602 Tõravere, Estonia
e-mail: ivan@aai.ee
² Estonian Academy of Sciences, 10130 Tallinn, Estonia
³ ICRANet, Piazza della Repubblica 10, 65122 Pescara, Italy
⁴ Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
⁵ Landau Institute for Theoretical Physics, Moscow 119334, Russia
⁶ Research Center for the Early Universe (RESCEU), Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan

Received: 23 December 2010
Accepted: 9 March 2011

Abstract

Aims. We follow the evolution of galaxy systems in numerical simulations. Our goal is to understand the role of density perturbations on various scales in the formation and evolution of the cosmic web.

Methods. We perform numerical simulations with the full power spectrum of perturbations, and with a spectrum cut at long wavelengths. In addition, we have one model, where we cut the intermediate waves. We analyse the density field and study void sizes and density field clusters in different models.

Results. Our analysis shows that the fine structure (groups and clusters of galaxies) are created by small-scale density perturbations of scale  ≤ 8 h^-1 Mpc. Filaments of galaxies and clusters are created by perturbations of intermediate scale from  ~ 8 to  ~ 32 h^-1 Mpc, and superclusters of galaxies by larger perturbations.

Conclusions. We conclude that the texture of the cosmic web is determined by density perturbations of the scales up to  ~ 100 h^-1 Mpc. Larger perturbations do not change the texture of the web, but modulate the richness of galaxy systems, and make voids emptier.