Accelerating Flat Universe and Analytic Study of the m-z Relation
نویسنده
چکیده
An accelerating flat universe with a variable cosmological term is obtained in the Robertson-Walker metric. The variable cosmological term is defined by the correction terms of the metric tensor field. Simple solutions of the scale factor and the cosmological term are shown. In this model of the universe, the magnitude-redshift relation is analytically studied to see if the model reproduces the tendency of the present observational data. The equation of state parameter γ is touched.
منابع مشابه
Exact Analytic Spectrum of Relic Gravitational Waves in Accelerating Universe
An exact analytic calculation is presented for the spectrum of relic gravi-tational waves in the scenario of accelerating Universe Ω Λ + Ω m = 1. The spectrum formula contains explicitly the parameters of acceleration, inflation , reheating, and the (tensor/scalar) ratio, so that it can be employed for a variety of cosmological models. We find that the spectrum depends on the behavior of the pr...
متن کاملDetermining the Geometry and the Cosmological Parameters of the Universe through SZE Cluster Counts
We study Sunyaev-Zel’dovich Effect (SZE) cluster counts in different cosmologies. It is found that even without the full knowledge of the redshift distribution of SZE clusters, one can still readily distinguish a flat universe with a cosmological constant from an open universe. We divide clusters into a low redshift group (with redshift z ≤ 0.5) and a high redshift group (with z ≥ 1), and compu...
متن کاملThe dark energy–dominated Universe
In this paper we investigate the epochs in which the Universe started accelerating and when it began to become dark energy–dominated (i.e., the dynamics of the expansion of the Universe dominated by the dark energy). We provide analytic expressions to calculate the redshifts of these epochs as a function of density parameters. Moreover, we review and discuss cosmological models with a dark ener...
متن کاملTest of Comoving Coordinate Frame by Low Magnitude-Redshift Relation
Observational evidence from a variety of sources points at an accelerating universe which is approximately spatially flat and with (ΩM ,ΩΛ)0 ≈ (0.3, 0.7). We have shown that for low redshifts, z ≤ 0.2, the metric of this cosmological model is equivalent to the de Sitter metric within one percent error. Among various coordinate descriptions for the flat de Sitter model two are most widely used, ...
متن کاملGrowth index in an accelerating universe
We obtain the exact analytic form of growth index (f = Ωm(a) ) at present epoch in a flat universe with including the constant equation of state of dark energy (ωde). For the cosmological constant (ωde = −1) we obtain γ = 0.5547 which is very close to the well known value 6/11. However, if ωde = −0.9, then γ gives rise to 0.6405. Ω 0 m dependence of γ is fairly small for the viable range of the...
متن کامل