相关论文: Status of Cosmological Parameters: $\Omega_0\appro…
I discuss the Hubble parameter $H_0$, the age of the universe $t_0$, the density $\Omega_0$, and the cosmological constant $\Lambda$. To focus the discussion, I concentrate on the issue of the value of the density $\Omega_0$ in currently…
The cosmological parameters that I will emphasize are the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the age of the universe $t_0$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino…
The cosmological parameters that I emphasize are the age of the universe $t_0$, the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino…
The discussion of cosmological parameters used to be a source of embarrassment to cosmologists. Today, measurements of the cosmological parameters are leading the way into the era of precision cosmology. The CMB temperature is measured to…
Recent observations by the Hubble Space Telescope of Cepheids in the Virgo cluster imply a Hubble Constant $H_0=80\pm17$\ km/sec/Mpc. We attempt to clarify some issues of interpretation of these results for determining the global…
In this review, the status of measurements of the matter density (Omega), the vaccuum energy density or cosmological constant (Lambda), the Hubble constant (H0), and ages of the oldest measured objects (t0) are summarized. Measurements of…
The ages of the oldest stellar objects in our galaxy provide an independent test of the current cosmological model as they give a lower limit to the age of the Universe. Recent accurate parallaxes by the Gaia space mission, accurate…
The set of cosmological density parameters ($\Omega_{0m}h_{0}^{2}$, $\Omega_{0k}h_{0}^{2}$, $\Omega_{0\Lambda}h_{0}^{2}$) and Hubble constant ($\hat{h}_{0}$) are useful for fundamental understanding of the universe from many perspectives.…
Some of the arguments which support the strong concensus for an $\Omega_o$ = 0.3, $\lambda_o$ = 0.7 model are reexamined. Corrections for Malmquist bias, local flow and metallicity suggest a revised value for $H_o$ of 63 $\pm$ 6 km/s/Mpc,…
We here update the derivation of precise values for the Hubble constant H_0, the age t_0 and the density parameter Omega*h^2 of the universe in the decaying neutrino theory for the ionisation of the interstellar medium (Sciama 1990 a,…
The following review presents an attempt to discuss various issues of current interest in Observational Cosmology, the selection of which as well as the emphasis given, reflects my own preference and biases. After presenting some…
Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…
We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…
Rapid progress has been made recently toward the measurement of cosmological parameters. Still, there are areas remaining where future progress will be relatively slow and difficult, and where further attention is needed. In this review,…
Cosmological parameters are constrained by a wide variety of observations. We examine the concordance diagram for modern measurements of the Hubble constant, the shape parameter from large scale structure, the cluster baryon fraction, and…
Determinations of the main cosmological parameters are reviewed and the implications for cold dark matter discussed. There is no longer an age problem for an $\Omega_o = 1, \Lambda = 0$ model and, if anything, there is now an age problem…
We present cosmological parameter constraints on flat cosmologies dominated by dark energy using various cosmological data including the recent Archeops angular power spectrum measurements. A likelihood analysis of the existing Cosmic…
We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…
The details of the CMB power spectrum are being revealed through the combined efforts of the world's CMBologists. The current data set constrains several cosmological parameters. A combination with other (non-lensing) constraints yields…
The Hubble constant, $H_0$, sets the scale of the size and age of the Universe and its determination from independent methods is still worthwhile to be investigated. In this article, by using the Sunyaev-Zel`dovich effect and X-ray surface…