Some Inhomogeneous Magnetized Viscous Fluid Cosmological Models with Varying Λ\Lambda

Some cylindrically symmetric inhomogeneous viscous fluid cosmological models with electro-magnetic field are obtained. To get a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous fluid is assumed to be a power function of mass density. Without assumin g any {\it ad hoc} law, we obtain a cosmological constant as a decreasing function of time. The behaviour of the electro-magnetic field tensor together with some p hysical aspects of the model are also discussed.Comment: 17 pages, 1 figur

Izvod kozmoloških modela V Bianchijeve vrste s volumnim trenjem i vremenski-ovisnim članom λ

Bianchi type V bulk viscous fluid cosmological models are investigated with dynamic cosmological term λ(t). Using a generation technique (Camci et al., 2001), it is shown that the Einstein\u27s field equations are solvable for any arbitrary cosmic scale function. Solutions for particular forms of cosmic scale functions are also obtained. The cosmological constant is found to be a decreasing function of time, which is supported by results from recent type Ia supernovae observations. Some physical and geometrical aspects of the models are also discussed.Istražujemo kozmološke modele V-e Bianchijeve vrste s volumnim trenjem i dinamičnim kozmološkim članom Λ(t). Primjenom metode izvođenja (Camci et al., 2001) pokazujemo da se Einsteinove jednadžbe polja mogu riješiti za proizvoljnu funkciju kozmičke mjere. Postigli smo rješenja za posebne funkcije kozmičkih mjera. Nalazimo da je kozmološka konstanta opadajuća funkcija vremena, što je u skladu s nedavnim opažanjima supernova Ia. Raspravljamo također neka fizička svojstva modela

Izvod kozmoloških modela V Bianchijeve vrste s volumnim trenjem i vremenski-ovisnim članom λ

Bianchi type V bulk viscous fluid cosmological models are investigated with dynamic cosmological term λ(t). Using a generation technique (Camci et al., 2001), it is shown that the Einstein\u27s field equations are solvable for any arbitrary cosmic scale function. Solutions for particular forms of cosmic scale functions are also obtained. The cosmological constant is found to be a decreasing function of time, which is supported by results from recent type Ia supernovae observations. Some physical and geometrical aspects of the models are also discussed.Istražujemo kozmološke modele V-e Bianchijeve vrste s volumnim trenjem i dinamičnim kozmološkim članom Λ(t). Primjenom metode izvođenja (Camci et al., 2001) pokazujemo da se Einsteinove jednadžbe polja mogu riješiti za proizvoljnu funkciju kozmičke mjere. Postigli smo rješenja za posebne funkcije kozmičkih mjera. Nalazimo da je kozmološka konstanta opadajuća funkcija vremena, što je u skladu s nedavnim opažanjima supernova Ia. Raspravljamo također neka fizička svojstva modela

Inhomogeneous Bulk Viscous Fluid Universe with Electromagnetic Field and Variable Λ\Lambda-Term

Cylindrically symmetric inhomogeneous cosmological model for bulk viscous fluid distribution with electromagnetic field is obtained. The source of the magnetic field is due to an electric current produced along the z-axis. $F_{12}$ is the non-vanishing component of electromagnetic field tensor. To get the deterministic solution, it has been assumed that the expansion $\theta$ in the model is proportional to the shear $\sigma$. The values of cosmological constant for these models are found to be small and positive at late time, which are consistent with the results from recent supernovae Ia observations. Physical and geometric aspects of the models are also discussed in presence and absence of magnetic field.Comment: 21 pages, 8 figure