83 research outputs found
1.4-GHz Luminosity Function of Galaxies from the Las Campanas Redshift Survey
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
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
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, , up to the first
order of the time . 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
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
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
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 and energy density
, 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 and (), which can correspond to (hyper) phantom fluid, and to a
high density universe. However if we assume prior that
then the favoured model is close to concordance
CDM model. Our results predict that in the considered model with
scaling fluids distant type Ia supernovae should be brighter than in
CDM model, while intermediate distant SNIa should be fainter than in
CDM model. We also investigate whether the model with scaling fluid is
actually preferred by data over CDM 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
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 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
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