Exact Bianchi-type VIII and IX models in the presence of zero-mass scalar fields

Exact Bianchi-type VIII and IX models in the presence of zero-mass scalar fields are presented, when the source of the gravitational field is a perfect fluid withP=. Some physical and geometrical properties of the models are also discussed.     

Vacuum Friedmann models in self-creation cosmology

The vacuum Friedmann models are investigated in self-creation theory of gravitation proposed by Barber. New solutions are obtained forK=±1, and some properties of the solutions are discussed. Only theK=0 solution in self-creation cosmology was previously shown.     

Bianchi type-VI0 models in self-creation cosmology

Spatially-homogenous and anisotropic Bianchi type-VI₀ cosmological models are obtained, in Barber's second self-creation theory of gravitation, both in vacuum and in the presence of perfect fluid with pressure equal to energy density. Some properties of the model are discussed.     

Exact bianchi type-II,VIII and IX cosmological models in scale-covariant theory of gravitation

Exact Bianchi types-II, VIII and IX cosmological models are obtained in the scale covariant theory of gravitation. Some physical and geometrical properties of the models are studied.     

Plane-symmetric vacuum in self-creation cosmology

Vacuum field equations for the static and non-static plane-symmetric metric are obtained in self-creation theory of gravitation proposed by Barber (1982). It is shown that, in both static and non-static cases, the only plane-symmetric solution in vacuum is the empty flat space-time of Einstein's theory. It is observed that this result is quite different from that of the Brans-Dicke and other scalar-tensor theories of gravitation.     

Vacuum friedmann model in self-creation cosmology

The field equations of the self-creation theory of gravitation proposed by Barber are solved for a vacuum with the aid of a space-time metric of Friedmann. Some physical properties of the solution are discussed.     

Bianchi type-I models in self-creation theory of gravitation

Spatially-homogeneous and anisotropic Bianchi type-I cosmological models are obtained, in Barber's second self-creation theory of gravitation, when the source of the gravitational field is a perfect fluid. Some physical and geometrical properties of the models are discussed.     

Some Bianchi-type cosmological models in a new scalar-tensor theory

Bianchi type I, III, V, VI₀, and Kantowski-Sachs type models have been investigated in a scalar tensor theory developed by Saez and Ballester (1985) and Saez (1985). The dynamical behaviour of the models has also been analyzed.     

Bianchi II,VIII, and IX viscous fluid cosmology

In this paper we study the exact solutions for a viscous fluid distribution in Bianchi II, VIII, and IX models. The metric is simplified by assuming a relationship between the coefficients of the metric tensor. Solutions are obtained in two special cases: in one an additional assumption is made where the matter density and the expansion scalar have a definite relation and in the other a barotropic equation of state of the formp= is assumed. While the Bianchi II solutions are already found in the literature the other two classes of solutions are apparently new.     

Bianchi type-I vacuum model in self-creation cosmology

A simple and elegant generalisation of the Kasner model is presented in a self-creation theory of gravitation, proposed by Barber by solving the field equations corresponding to the Bianchi type-I metric. Some physical properties of the model are discussed.     

Nonexistence of static conformally-flat solutions in self-creation cosmology

It is shown that the merger times of a satellite galaxy moving on the periphery of the primary galaxy obtained under the impulsive and adiabatic approximations reduce to the decay time predicted by Chandrasekhar's formula for dynamical friction if the satellite galaxy is regarded as a mass point.     

A static conformally-flat vacuum model in self-creation cosmology

Vacuum field equations for the conformally-flat spherically-symmetric static space-time are obtained in a self-creation theory of gravitation proposed by Barber. It is shown that the most general conformally-flat spherically-symmetric static vacuum model in this theory represents only purely flat space-time.     

Bianchi type-V radiating model in self-creation cosmology

The spatially-homogeneous and anisotropic cosmological model in self-creation theory of gravitation proposed by Barber, is obtained in the presence of perfect fluid with disordered radiation and the metric is of Bianchi type-V. Some physical properties of the model are discussed.     

Birkhoff-type theorem for electromagnetic fields in self-creation cosmology

A result having formal similarity to Birkhoff's theorem in general relativity has been proved in the presence of electromagnetic fields in a self-creation theory of gravitation proposed by Barber, when the scalar field is independent of time.     

Plane symmetric string cosmological models in self-creation theory of gravitation

Plane Symmetric string cosmological models are presented in Barber’s second self creation theory of gravitation and obtained Einstein’s plane symmetric string cosmological models as a special case. Some physical and geometrical properties of the models are also discussed.     

Exact bianchi type-II,VIII, and IX cosmological models with matter and electromagnetic fields in Lyra's manifold

Spatially-homogeneous and anisotropic Bianchi type-II, VIII, and IX stiff-fluid cosmological models in the presence of source-free electromagnetic fields are obtained in Lyra's manifold. Some properties of the models are also discussed.     

Certain vacuum Bianchi-type models in a new relativistic theory of gravitation

The vacuum Bianchi type-I, III, V, VI₀ and Kantowski-Sachs models have been obtained in a new scalar-tensor theory formulated by Lau and Prokhovnik (1986) under the assumption of a certain relationship between the cosmological term and the scalar field . The dynamical behaviour of these models have been studied.     

Exact Brans-Dicke-Bianchi types-II,VIII, and IX stiff matter solutions

Exact solutions of the Brans-Dicke field equations of Bianchi types-II, VIII, and IX are derived. The solutions represent locally rotationally symmetric universes with stiff matter content.     

Axially symmetric radiating cosmological model in a self-creation cosmology

An axially symmetric space time is considered in the presence of a perfect fluid source in Barbers (Gen. Relativ. Gravit. 14, 117, 1982) second self creation theory of gravitation. An exact radiating cosmological model is presented using a relation between the metric potentials. Some physical and kinematical properties of the model are also discussed.     

Bianchi type-I Universe filled with disordered radiation in self-creation cosmology

A spatially homogeneous and anisotropic cosmological model in self-creation theory of gravitation proposed by Barber is obtained when the source of the gravitational field is a perfect fluid with disordered radiation and the metric is of Bianchi type-I. Some physical properties of the model are discussed.