Vacuum Bianchi type-VI0 cosmological models in Ross and Dunn theories of gravitation

Spatially-homogeneous and anisotropic-vacuum Bianchi type-VI₀ cosmological models are obtained in scalar-tensor theories of gravitation proposed by Ross and Dunn. Some physical properties of the models are also discussed.     

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.     

Vacuum bianchi type V and VI0 cosmological models in a new scalar-tensor theory of gravitation

Vacuum Bianchi type V and VI₀ cosmological models obtained in a new scalar-tensor theory of gravitation proposed by Schmidtet al. Some physical properties of these models are also discussed.     

Bianchi type-VI0 cosmological models in schwinger's scalar-tensor theory

Spatially-homogeneous and anisotropic Bianchi type-VI₀ cosmological models are obtained in the scalar-tensor theory of gravitation proposed by Schwinger, both in vacuum and in the presence of perfect fluid with pressure equal to energy density. Some properties of the models are discussed.     

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.     

Bianchi type-VI0 cosmological model in the general scalar-tensor theory of gravitation

The exact Bianchi type-VI₀ stiff-fluid cosmological model is obtained in the Nordtvedt-Barker general scalar-tensor theory of gravitation. Some properties of the model are discussed.     

Exact Bianchi type II, VIII and IX string cosmological models in General Relativity and self-creation theory of gravitation

Exact Bianchi type II, VIII and IX String cosmological models are obtained in Einstein’s theory of gravitation and Barber’s (1982) second self-creation theory of gravitation. Some physical and geometrical properties of the models are also discussed.     

Bianchi type-II, VIII & IX perfect fluid magnetized cosmological models in Brans-Dicke theory of gravitation

Spatially homogeneous Bianchi type-II, VIII & IX charged perfect fluid cosmological models in Brans-Dicke theory of gravitation are obtained and presented. Various physical and geometrical features of the models are also 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.     

Bianchi type-VI0 vacuum model in the general scalar-tensor theory of gravitation

The spatially-homogeneous and anisotropic Bianchi type-VI₀ cosmological model is obtained in the Nordtvedt-Barker general scalar-tensor theories of gravitation. Exact solutions of the Nordtvedt-Barker field equations in vacuum are presented and studied.     

Vacuum Bianchi type-III cosmological models in Ross and Dunn theories of gravitation

Spatially-homogeneous and anisotropic-vacuum Bianchi type-III cosmological models are obtained in scalar-tensor theories of gravitation proposed by Ross and Dunn. Some physical properties of the models are also discussed.     

Exact Bianchi type II, VIII and IX string cosmological models in Saez-Ballester theory of gravitation

Exact Bianchi type II, VIII and IX String cosmological models are obtained in the Saez-Ballester theory of gravitation. Some physical and geometrical properties of the models are studied.     

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.     

Bianchi type-I string cosmological models in bimetric theory of gravitation

Bianchi type-I string cosmological models are obtained in bimetric theory of gravitation proposed by Rosen (Gen. Relativ. Gravit. 4:435, 1973). Established the existence of string cosmological models, unlike the earlier authors, in this theory and studied some physical and geometrical properties.     

Non-existence of cosmic strings in bimetric theory of gravitation

Bianchi type cosmological models are considered in Bimetric theory of gravitation proposed by Rosen (1973) in the context of cosmic strings. It is interesting to note that cosmic strings do not occur in Bianchi type cosmologies. This revised version was published online in July 2006 with corrections to the Cover Date.     

On Bianchi Type-I Mesonic Cosmological Model in Bimetric Theory

Anisotropic spatially homogeneous Bianchi type-I cosmological model in bimetric theory of gravitation (Rosen, 1973) is considered. It is shown that the Bianchi type-I cosmological model does not exist in case of both meson field and mesonic perfect fluid (with or without mass parameter). Hence only vacuum models can be obtained (Reddy and Venkateswarlu, 1989). This revised version was published online in July 2006 with corrections to the Cover Date.     

Vacuum bianchi type-V cosmological models in Ross and Dunn scalar-tensor theories of gravitation

It is shown that the relativistic analogues of vacuum Bianchi type-V cosmological models, in the scalar-tensor theories of gravitation proposed by Ross and Dunn, do not exist.     

Time dependent viscous string cloud cosmological models

Bianchi type-I string cosmological models are studied in Saez-Ballester theory of gravitation when the source for the energy momentum tensor is a viscous string cloud coupled to gravitational field. The bulk viscosity is assumed to vary with time and is related to the scalar expansion. The relationship between the proper energy density ρ and string tension density λ are investigated from two different cosmological models.     

Radial velocities in the open cluster Trumpler 14

Spatially-homogenous and anisotropic Bianchi type-II and III 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 models are discussed.     

On seeliger's paradox

It is shown that there do not exist spatially-homogeneous and anisotropic Bianchi type-I cosmological models in Rosen's (1973) bi-metric theory of gravitation when the source of the gravitational field is a perfect fluid distribution. A vacuum cosmological model, in this theory, is presented and studied.