529 research outputs found

    Kolmogorov stochasticity parameter measuring the randomness in Cosmic Microwave Background

    Full text link
    The Kolmogorov stochasticity parameter (KSP) is applied to quantify the degree of randomness (stochasticity) in the temperature maps of the Cosmic Microwave Background radiation maps. It is shown that, the KSP for the WMAP5 maps is about twice higher than that of the simulated maps for the concordance \LambdaCDM cosmological model, implying the existence of a randomizing effect not taken into account in the model. As was revealed recently, underdense regions in the large scale matter distributions, i.e the voids, possess hyperbolic and hence randomizing properties. The degree of randomness for the Cold Spot appears to be about twice higher than the average over the mean temperature level spots in the sky, which supports the void nature of the Cold Spot. Kolmogorov's parameter then acts as a quantitative tracer of the voids via CMB.Comment: A&A Lett (in press), 2 pages, 1 Tabl

    Are There Echoes From The Pre-Big Bang Universe? A Search for Low Variance Circles in the CMB Sky

    Full text link
    The existence of concentric low variance circles in the CMB sky, generated by black-hole encounters in an aeon preceding our big bang, is a prediction of the Conformal Cyclic Cosmology. Detection of three families of such circles in WMAP data was recently reported by Gurzadyan & Penrose (2010). We reassess the statistical significance of those circles by comparing with Monte Carlo simulations of the CMB sky with realistic modeling of the anisotropic noise in WMAP data. We find that the circles are not anomalous and that all three groups are consistent at 3sigma level with a Gaussian CMB sky as predicted by inflationary cosmology model

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

    Get PDF
    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.

    Ellipticity in Cosmic Microwave Background as a Tracer of Large-Scale Universe

    Get PDF
    Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data confirm the ellipticity of anisotropies of Cosmic Microwave Background (CMB) maps, found previously for Boomerang and WMAP 1-year high sensitivity maps. The low noise level of the WMAP latter data enable also to show that, the ellipticity is a property not described by the conventional cosmological model fitting the power spectrum of CMB. As a large scale anomaly, the ellipticity characteristics are consistent with the effect of geodesics mixing occurring in hyperbolic Universe. Its relation to other large scale effects, i.e. to suppressed low multipoles, as well as to dark energy if the latter is due to vacuum fluctuations, is then an arising issue.Comment: to appear in Phys. Lett.

    Collective relaxation of stellar systems revisited

    Full text link
    The chaos in stellar systems is studied using the theory of dynamical systems and the Van Kampen stochastic differential equation approach. The exponential instability (chaos) of spherical N-body gravitating systems, already known previously, is confirmed. The characteristic timescale of that instability is estimated confirming the collective relaxation time obtained by means of the Maupertuis principle.Comment: A & A (in press), 3 pages, to match the published versio

    Kolmogorov cosmic microwave background sky

    Full text link
    A new map of the sky representing the degree of randomness in the cosmic microwave background (CMB) temperature has been obtained. The map based on estimation of the Kolmogorov stochasticity parameter clearly distinguishes the contribution of the Galactic disk from the CMB and reveals regions of various degrees of randomness that can reflect the properties of inhomogeneities in the Universe. For example, among the high randomness regions is the southern non-Gaussian anomaly, the Cold Spot, with a stratification expected for the voids. Existence of its counterpart, a Northern Cold Spot with almost identical randomness properties among other low-temperature regions is revealed. By its informative power, Kolmogorov's map can be complementary to the CMB temperature and polarization sky maps.Comment: A & A (in press), to match the published version, 4 pages, 5 figs, 2 Table

    Hidden invariance in Gurzadyan-Xue cosmological models

    Full text link
    The dark energy formula derived by Gurzadyan and Xue which leads to a value fitting the SN data, provides a scaling relation between the physical constants and cosmological parameters and defines a set of cosmological models. In previous works we have considered several of those models and derived the cosmological equations for each case. In this letter, we present the phase portrait analysis of those models. Surprisingly we found, first, that the separatrix in the phase space which determines the character of solutions depends solely on the value of the current matter density. Namely, at Ωm>2/3\Omega_m>2/3 the equations describe Friedmannian Universe with the classical singularity at the beginning. While at Ωm<2/3\Omega_m<2/3 all solutions for all models start with zero density and non vanishing scale factor. Secondly, more remarkable, the value Ωsep=2/3\Omega_{sep}=2/3 defining the separatrix is the same for all models, which reveales an underlying invariance hidden in the models, possibly, due to the basic nature of the GX-scaling.Comment: to appear in Physics Letters

    Chaotic Phenomena in Astrophysics and Cosmology

    Full text link
    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
    • …
    corecore