83 research outputs found

    1.4-GHz Luminosity Function of Galaxies from the Las Campanas Redshift Survey

    Full text link
    A preliminary 1.4 GHz RLF at redshift of about 0.14 is derived from the Las Campanas Redshift Survey (LCRS) and the NVSS radio data. No significant evolution has been found at this redshift in comparison to the 'local' RLF.Comment: 2 pages including 2 Postscript figures, uses crckapb10.st

    Investigation of galactic alignment in LSC galaxy clusters

    Get PDF
    We investigate the galactic axes orientations within 18 selected clusters, sub-structures of the Local Supercluster. For every cluster we map the parameter \Delta_{11} (Flin & God{\l}owski 1986) describing the galactic axes alignment with respect to a cluster pole changing along the entire celestial sphere. The resulting maps are analyzed for correlations of its maxima with directions from the cluster centre to 1.) the derived `physical' cluster poles, 2.) the Local Supercluster centre, 3.) the Virgo A centre and 4.) the Earth, i.e. along the line of sight (LOS). The strong maxima - with one exception - exist only for non-spiral (NS) sub-samples, with the maximum well correlated with the LOS direction. For clusters with a clearly defined weak maximum the conclusion generally does not change. For the spiral (S) sub-samples the maps are usually at the random noise level. In these cases a weaker, but still existent correlation with the LOS is observed and no other evident correlations are noted. We conclude that the strong systematic effect, generated by the process of galactic axis de-projection from its optical image, is present in the catalogue data. With the use of a simple model for the systematic effect we are able to reproduce the main characteristic features of the maps for NS galaxies. We note, however, a few clusters showing significant differences with respect to this model.Comment: LaTeX (21 pages, 10 gif figures); MNRAS, accepte

    Cosmological applications in Kaluza-Klein theory

    Full text link
    The field equations of Kaluza-Klein (KK) theory have been applied in the domain of cosmology. These equations are solved for a flat universe by taking the gravitational and the cosmological constants as a function of time t. We use Taylor's expansion of cosmological function, Λ(t)\Lambda(t), up to the first order of the time tt. The cosmological parameters are calculated and some cosmological problems are discussed.Comment: 14 pages Latex, 5 figures, one table. arXiv admin note: text overlap with arXiv:gr-qc/9805018 and arXiv:astro-ph/980526

    Quantum Stephani Universe in vicinity of the symmetry center

    Full text link
    We study a class of spherically symmetric Stephani cosmological models in the presence of a self-interacting scalar field in both classical and quantum domains. We discuss the construction of `canonical' wave packets resulting from the solutions of a class of Wheeler-DeWitt equations in the Stephani Universe. We suggest appropriate initial conditions which result in wave packets containing some desirable properties, most importantly good classical and quantum correspondence. We also study the situation from de-Broglie Bohm interpretation of quantum mechanics to recover the notion of time and compare the classical and Bohmian results. We exhibit that the usage of the canonical prescription and appropriate choices of expansion coefficients result in the suppression of the quantum potential and coincidence between classical and Bohmian results. We show that, in some cases, contrary to Friedmann-Robertson-Walker case, the bound state solutions also exist for all positive values of the cosmological constant.Comment: 22 pages, 19 figures, to appear in JCA

    On the investigations of galaxy redshift periodicity

    Get PDF
    In this article we present a historical review of study of the redshift periodicity of galaxies, starting from the first works performed in the seventies of the twentieth century until the present day. We discuss the observational data and methods used, showing in which cases the discretization of redshifts was observed. We conclude that galaxy redshift periodisation is an effect which can really exist. We also discussed the redshift discretization in two different structures: the Local Group of galaxies and the Hercules Supercluster. Contrary to the previous studies we consider all galaxies which can be regarded as a structure member disregarding the accuracy of velocity measurements. We applied the power spectrum analysis using the Hann function for weighting, together with the jackknife error estimator. In both the structures we found weak effects of redshift periodisation.Comment: 10 pages, 4 figures, to be published in Part. and Nucl. Lett. 200

    Equation of state for Universe from similarity symmetries

    Full text link
    In this paper we proposed to use the group of analysis of symmetries of the dynamical system to describe the evolution of the Universe. This methods is used in searching for the unknown equation of state. It is shown that group of symmetries enforce the form of the equation of state for noninteracting scaling multifluids. We showed that symmetries give rise the equation of state in the form p=Λ+w1ρ(a)+w2aβ+0p=-\Lambda+w_{1}\rho(a)+w_{2}a^{\beta}+0 and energy density ρ=Λ+ρ01a3(1+w)+ρ02aβ+ρ03a3\rho=\Lambda+\rho_{01}a^{-3(1+w)}+\rho_{02}a^{\beta}+\rho_{03}a^{-3}, which is commonly used in cosmology. The FRW model filled with scaling fluid (called homological) is confronted with the observations of distant type Ia supernovae. We found the class of model parameters admissible by the statistical analysis of SNIa data. We showed that the model with scaling fluid fits well to supernovae data. We found that Ωm,00.4\Omega_{\text{m},0} \simeq 0.4 and n1n \simeq -1 (β=3n\beta = -3n), which can correspond to (hyper) phantom fluid, and to a high density universe. However if we assume prior that Ωm,0=0.3\Omega_{\text{m},0}=0.3 then the favoured model is close to concordance Λ\LambdaCDM model. Our results predict that in the considered model with scaling fluids distant type Ia supernovae should be brighter than in Λ\LambdaCDM model, while intermediate distant SNIa should be fainter than in Λ\LambdaCDM model. We also investigate whether the model with scaling fluid is actually preferred by data over Λ\LambdaCDM model. As a result we find from the Akaike model selection criterion prefers the model with noninteracting scaling fluid.Comment: accepted for publication versio

    Dynamics of the Universe with global rotation

    Full text link
    We analyze dynamics of the FRW models with global rotation in terms of dynamical system methods. We reduce dynamics of these models to the FRW models with some fictitious fluid which scales like radiation matter. This fluid mimics dynamically effects of global rotation. The significance of the global rotation of the Universe for the resolution of the acceleration and horizon problems in cosmology is investigated. It is found that dynamics of the Universe can be reduced to the two-dimensional Hamiltonian dynamical system. Then the construction of the Hamiltonian allows for full classification of evolution paths. On the phase portraits we find the domains of cosmic acceleration for the globally rotating universe as well as the trajectories for which the horizon problem is solved. We show that the FRW models with global rotation are structurally stable. This proves that the universe acceleration is due to the global rotation. It is also shown how global rotation gives a natural explanation of the empirical relation between angular momentum for clusters and superclusters of galaxies. The relation JM2J \sim M^2 is obtained as a consequence of self similarity invariance of the dynamics of the FRW model with global rotation. In derivation of this relation we use the Lie group of symmetry analysis of differential equation.Comment: Revtex4, 22 pages, 5 figure
    corecore