Showing papers on "Deceleration parameter published in 1979"

Observable relations in an inhomogeneous self-similar cosmology

Abstract: An exact self-similar solution is taken in general relativity as a model for an inhomogeneous cosmology. The self-similarity property means (conceptually) that the model is scale-free and (mathematically) that its essential parameters are functions of only one dimensionless variable zeta (equivalentct/R, where R and t are distance and time coordinates and c is the velocity of light). It begins inhomogeneous (zeta=0 or t=0), and tends to a homogeneous Einstein--de Sitter type state as zeta (or t) ..-->..infinity. Such a model can be used (a) for evaluating the observational effects of a clumpy universe; (b) for studying astrophysical processes such as galaxy formation and the growth and decay of inhomogeneities in initially clumpy cosmologies; and (c) as a relativistic basis for cosmological models with extended clustering of the de Vaucouleurs and Peebles types. The model has two adjustable parameters, namely, the observer's coordinate zeta/sub 0/ and a constant ..cap alpha../sub s/ that fixes the effect of the inhomogeneity. Expressions are obtained for the redshift, Hubble parameter, deceleration parameter, magnitude-redshift relation, and (number density of objects) --redshift relation. Expected anisotropies in the 3 K microwave background are also examined. There is no conflict with observation if zeta/sub 0//..cap alpha../sub s/> or approx.more » =10, and four tests of the model are suggested that can be used to further determine the acceptability of inhomogeneous cosmologies of this type. The ratio ..cap alpha../sub s//zeta/sub 0/ on presently available data is ..cap alpha../sub s//zeta/sub 0/< or approx. =10% and this, loosely speaking, means that the universe at the present epoch is globally homogeneous to within about 10%.« less

Scale covariance and G-varying cosmology. IV - The log N-log S relation

Abstract: The traditional radio counts N(S) and radio source models are studied within the framework of the scale-covariant cosmology developed to investigate whether the relative strength of the gravitational and electromagnetic constants is a function of cosmological epoch. It is found that a gravitational constant G varying as the inverse of t, where t is the epoch in atomic units, is consistent with all the data analyzed. For a wide class of models the present cosmology allows a finer discrimination of the deceleration parameter than does standard theory. The results, when combined with those of previous papers, namely, those from radio and optical flux and angular-diameter data analysis, favor an open universe.

EVOLUTION OF QUASARS WITH RESOLVED COMPONENTS AND DETERMINATION OF DECELERATION PARAMETER q_0

Abstract: With the largest separation D of the components as a parameter for standard candle classification of composite quasars, we obtain the redshift-magnitude relation with fairly good correlation, and the deceleration parameter q_0 derived from it is 0.9—1.5. It shows that the universe is probably closed, and statistics shows that in the early stages of the universe there were only quasars with smaller D and not until the later stages did quasars with bigger D appear. This is a support for the evolutionary model of the universe, i.e. the big bang model. Statistical results also indicate that during the evolution of this type of quasars their optical luminosity and radio luminosity both decrease gradually, and the rates of decline are dM/dD =7~m±3~m/MPC and dS/dD=9~m±1~m/MPC respectively.