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Title: Evolution of cosmic structures in different environments in the quasispherical Szekeres model

Abstract

This paper investigates evolution of cosmic structures in different environments. For this purpose the quasispherical Szekeres model is employed. The Szekeres model is an exact solution of the Einstein field equations within which it is possible to describe more than one structure. In this way investigations of the evolution of the cosmic structures presented here can be freed from such assumptions as a small value of the density contrast. Also, studying the evolution of two or three structures within one framework enables us to follow the interaction between these structures and their impact on the evolution. Main findings include a conclusion that small voids surrounded by large overdensities evolve slower than large, isolated voids do. On the other hand, large voids enhance the evolution of adjacent galaxy superclusters which evolve much faster than isolated superclusters.

Authors:
 [1]
  1. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warsaw (Poland)
Publication Date:
OSTI Identifier:
21011051
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevD.75.043508; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGICAL MODELS; COSMOLOGY; DENSITY; EINSTEIN FIELD EQUATIONS; EXACT SOLUTIONS; GALAXIES; GALAXY CLUSTERS

Citation Formats

Bolejko, Krzysztof. Evolution of cosmic structures in different environments in the quasispherical Szekeres model. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.043508.
Bolejko, Krzysztof. Evolution of cosmic structures in different environments in the quasispherical Szekeres model. United States. doi:10.1103/PHYSREVD.75.043508.
Bolejko, Krzysztof. Thu . "Evolution of cosmic structures in different environments in the quasispherical Szekeres model". United States. doi:10.1103/PHYSREVD.75.043508.
@article{osti_21011051,
title = {Evolution of cosmic structures in different environments in the quasispherical Szekeres model},
author = {Bolejko, Krzysztof},
abstractNote = {This paper investigates evolution of cosmic structures in different environments. For this purpose the quasispherical Szekeres model is employed. The Szekeres model is an exact solution of the Einstein field equations within which it is possible to describe more than one structure. In this way investigations of the evolution of the cosmic structures presented here can be freed from such assumptions as a small value of the density contrast. Also, studying the evolution of two or three structures within one framework enables us to follow the interaction between these structures and their impact on the evolution. Main findings include a conclusion that small voids surrounded by large overdensities evolve slower than large, isolated voids do. On the other hand, large voids enhance the evolution of adjacent galaxy superclusters which evolve much faster than isolated superclusters.},
doi = {10.1103/PHYSREVD.75.043508},
journal = {Physical Review. D, Particles Fields},
number = 4,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • Structure formation in the Szekeres model is investigated. Since the Szekeres model is an inhomogeneous model with no symmetries, it is possible to examine the interaction of neighboring structures and its impact on the growth of a density contrast. It has been found that the mass flow from voids to clusters enhances the growth of the density contrast. In the model presented here, the growth of the density contrast is almost 8 times faster than in the linear approach.
  • We consider the Goode-Wainwright representation of the Szekeres cosmological models and calculate the Taylor expansion of the luminosity distance in order to study the effects of the inhomogeneities on cosmographic parameters. Without making a particular choice for the arbitrary functions defining the metric, we Taylor expand up to the second order in redshift for Family I and up to the third order for Family II Szekeres metrics under the hypotesis, based on observation, that local structure formation is over. In a conservative fashion, we also allow for the existence of a non null cosmological constant.
  • We show that the full dynamical freedom of the well known Szekeres models allows for the description of elaborated 3-dimensional networks of cold dark matter structures (over-densities and/or density voids) undergoing ''pancake'' collapse. By reducing Einstein's field equations to a set of evolution equations, which themselves reduce in the linear limit to evolution equations for linear perturbations, we determine the dynamics of such structures, with the spatial comoving location of each structure uniquely specified by standard early Universe initial conditions. By means of a representative example we examine in detail the density contrast, the Hubble flow and peculiar velocities ofmore » structures that evolved, from linear initial data at the last scattering surface, to fully non-linear 10–20 Mpc scale configurations today. To motivate further research, we provide a qualitative discussion on the connection of Szekeres models with linear perturbations and the pancake collapse of the Zeldovich approximation. This type of structure modelling provides a coarse grained—but fully relativistic non-linear and non-perturbative —description of evolving large scale cosmic structures before their virialisation, and as such it has an enormous potential for applications in cosmological research.« less
  • We present a new formulation of the two classes of Szekeres solutions of the Einstein field equations, which unifies the solutions as regards their dynamics, and relates them to the Friedmann-Robertson-Walker (FRW) cosmological models in a particularly transparent way. This reformulation enables us to give a general analysis of the scalar polynomial curvature singularities of the solutions, and of their evolution in time. In particular, the solutions which are close to an FRW model near the initial singularity, or in the late stages of evolution, are identified.
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