Recovering the Internal Dynamics and the Shapes of Galaxy Clusters: Virgo Cluster

We describe a method for recovering of the substructure, internal dynamics and geometrical shapes of clusters of galaxies. Applying the method to the Virgo cluster, we, first, reveal the substructure of the central 4 arc degree field of the Virgo cluster by means of S-tree technique. The existence of three main subgroups of galaxies is revealed and their dynamical characteristics are estimated. Then, using the previously suggested technique (Gurzadyan and Rauzy 1997), the bulk flow velocities of the subgroups are evaluated based on the distribution of the redshifts of the galaxies. The results enable us also to obtain a secure indication of the elongation of the Virgo cluster and its positional inclination.Comment: to appear in Int.Journ.Mod.Phys.

Chaotic Phenomena in Astrophysics and Cosmology

Chaos as typical property of non-linear systems has revealed its crucial role in various problems of astrophysics and cosmology. The problems discussed at these lectures include planetary dynamics, galactic dynamics, reconstruction of the substructure of clusters of galaxies, instability in Wheeler-DeWitt superspace. The choice of the problems aimed to show also the diversity of approaches and mathematical tools, which include the geometric criterion (Ricci) of relative instability in many dimensional systems, the estimation of Kolmogorov-Sinai entropy, the hyperbolicity in pseudo-Riemannian spaces, etc.Comment: Lectures at the Xth Brazilian School of Cosmology and Gravitation, July-August, Rio de Janeiro, 200

Kolmogorov Complexity, Cosmic Background Radiation and Irreversibility

We discuss the algorithmic information approach to the analysis of the observational data on the Universe. Kolmogorov complexity is proposed as a descriptor of the Cosmic Microwave Background (CMB) radiation maps. An algorithm of computation of the complexity is described, applied, first, to toy models and then, to the data of the Boomerang experiment. The sky maps obtained via the summing of two independent Boomerang channels reveal threshold independent behavior of the mean ellipticity of the anisotropies, thus indicating correlations present in the sky signal and possibly carrying crucial information on the curvature and the non-Friedmannian, i.e. accelerated expansion of the Universe. Similar effect has been detected for COBE-DMR 4 year maps. Finally, as another application of these concepts, we consider the possible link between the CMB properties, curvature of the Universe and arrows of time.Comment: Talk at XXII Solvay Conference on Physics "The Physics of Communication" (Delphi, November 24-29, 2001); the discussion include