Bianchi type-V cosmological models with perfect fluid and dark energy

We consider a self-consistent system of Bianchi type-V cosmology and binary mixture of perfect fluid and dark energy. The perfect fluid is taken to be one obeying the usual equation of state p=γ ρ with γ∈[0,1]. The dark energy is considered to be either the quintessence or Chaplygin gas. Exact solutions to the corresponding Einstein equations are obtained as a quadrature. The cases of disordered radiation and models with power-law and exponential expansion have discussed in detail. For large t, the models tend to be isotropic.     

Bianchi type-V anisotropic cosmological models in certain theories of gravitation with perfect fluid distribution

Exact Bianchi type-V cosmological models are presented in Einstein’s theory of gravitation with cosmological constant Λ in case of perfect fluid distribution. Also obtained Bianchi type-V cosmological models in a scalar-tensor theory of gravitation proposed by Saez and Ballester (1986) in case of perfect fluid distribution using and without using negative constant deceleration parameter. Some physical and geometrical properties of the models are also discussed.     

Bianchi type-V universe with wet dark fluid

The Bianchi type-V universe filled with dark energy from a wet dark fluid has been considered. A new equation of state for the dark energy component of the universe has been used. It is modeled on the equation of state p=γ(ρ?ρ _? ) which can describe a liquid, for example water. The exact solutions to the corresponding field equations are obtained in quadrature form. The solution for constant deceleration parameter have been studied in detail for power-law and exponential forms both. The case $\gamma =\frac{1}{3}$ has been also analysed.     

Bianchi type-V cosmological model with purely magnetic solution

In the present paper we study some new aspects of the Bianchi type-V space time. The Electric and Magnetic parts of Weyl tensors are calculated in terms of tilted congruence and discussed the purely magnetic Weyl tensor. Einstein field equations for purely magnetic space time are obtained and solution of such field equations called purely magnetic solution. To get deterministic solutions of the field equations we consider a new law of variation of average scale factor which yields time dependent deceleration parameter. Certain physical and geometrical properties of the model are also discussed.     

LRS Bianchi type-V universes filled with matter and radiation

In this paper we have investigated some LRS Bianchi type-V cosmologicla models representing a viscous fluid distribution with a null electromagnetic field and streaming neutrinos. Various physical and kinematical features of these models have also been explored.     

Inhomogeneous generalizations of Bianchi Type VI h universes with stiff perfect fluid and radiation

Families of inhomogeneous models filled with a stiff perfect fluid and radiation have been derived in which there is no flow of total momentum. The models are the generalizations of those of Bianchi Type VI _h and are discussed for some particular forms of the arbitrary functions appearing in them.     

Bianchi type-II perfect fluid solutions

It is shown that the recent new Bianchi type-II solutions of Hajj-Boutros (1986a, b) do not exist. We present a consistent method for perfect fluid solutions in this paper.     

Bianchi type-III universe with perfect fluid

We study Bianchi type-III cosmological model filled with perfect fluid in the presence of cosmological constant Λ(t). The Hubble law utilised yields a constant value of deceleration parameter. Physical and Kinematical properties of the model have also studied.      

Comment on the Bianchi type-V solution in the scale-covariant theory

We make some critical remarks on the recent papers by Beesham (1986a-c) concerning exact solutions of the scale-covariant theory.     

A class of new Bianchi I perfect fluid space-times

A procedure to generate new exact solutions to Einstein equations for perfect fluids is applied to LRS Bianchi type I line-element. Starting from some known solutions a class of new perfect fluid solutions of Bianchi type I are presented. The physical and kinematical properties of spatially homogeneous and anisotropic cosmological models are studied.     

Some new Bianchi type-I perfect fluid solutions

We present a simple method to construct some new perfect fluid solutions from known Bianchi type-I solutions.     

A note on the magnetic perfect fluid Bianchi type-VIo solutions

We make some comments concerning the magnetic perfect fluid Bianchi type-VI_o solutions given recently by Royet al. (1985a).     

Bianchi Type-III stiff fluid cosmological model in general relativity

In this paper, we have investigated a tilted Bianchi Type-III stiff fluid cosmological model in general relativity. To get a determinate solution, we have assumed a condition A=(BC) ⁿ between metric potentials. The various physical and geometrical aspects of the model are discussed.     

Bianchi type-VI0 and type-VIh perfect fluid solutions

We present a consistent method to construct some new Bianchi type-VI₀ and type-VI_h perfect fluid solutions from known solutions. The corresponding seed solutions are due to Collins (1971).     

Bianchi type-V cosmological model with perfect fluid using negative constant deceleration parameter in a scalar tensor theory based on Lyra Manifold

An exact Bianchi type-V perfect fluid cosmological model is obtained in a scalar tensor theory proposed by Sen (Z. Phys. 149:311, 1957) based on Lyra Manifold in case of β is a constant and it is shown that this cosmological model exists only in the case of Radiation Universe (ρ=3p) if β is a function of ‘t’ using negative constant deceleration parameter. Some physical and geometrical properties of these models are discussed.     

A Bianchi type I tilted universe

The Bianchi type I cosmological models have been extensively studied in the past especially as examples of the homogeneous shearing universe. This paper presents a tilted universe solution admitting this group of motion where the velocity field is shear-free but there is an energy flux term.     

Numerical nucleosynthesis results for Bianchi type-V cosmological models

Results of numerical calculations of helium-4 and deuterium abundances in a wide range of Bianchi type-V locally rotationally-symmetric cosmological models are presented. The tabulated element abundances show that these models generically yield helium fractions which are unacceptably large compared with the available observational data.     

Mesonic stiff fluid distribution in five dimensional Bianchi type space time

In this paper, we have constructed mesonic stiff fluid cosmological models in five dimensional LRS Bianchi type-I and Bianchi type-VI₀ space times in general theory of relativity. Some physical and geometrical properties of the models are discussed.     

Inhomogeneous generalizations of Bianchi type VIh models with perfect fluid

Inhomogeneous universes admitting an AbelianG ₂ of isometry and filled with perfect fluid have been derived. These contain as special cases exact homogeneous universes of Bianchi type VI_h.Many of these universes asymptotically tend to homogeneous Bianchi VI_h universes. The models have been discussed for their physical and kinematical behaviours.