相关论文: Cosmological Parameters and Hyper-Parameters: The …
The cosmological parameters that I discuss are the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the age of the universe $t_0$, the average density $\Omega_0$, and the cosmological constant $\Lambda$. To focus the discussion,…
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 first section discusses a recalibration of the luminosity-linewidth technique and its use in a determination of H_0. The recalibration introduces (i) new cluster calibration data, (ii) new corrections for reddening as a function of…
We present a numerical method to estimate the lensing parameters and the Hubble constant H_0 from quadruply imaged gravitational lens systems. The lens galaxy is modeled using both separable deflection potentials and constant mass-to-light…
Measurements of the Cosmic Microwave Background Radiation (CMBR) provide a powerful tool for measuring the primary cosmological parameters. However, there is a large degree of parameter degeneracy in simultaneous measurements of the matter…
In this article, we employ a machine learning (ML) approach for the estimations of four fundamental parameters, namely, the Hubble constant ($H_0$), matter ($\Omega_{0m}$), curvature ($\Omega_{0k}$) and vacuum ($\Omega_{0\Lambda}$)…
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,…
We present a determination of the Hubble constant from the joint, free-form analysis of 8 strongly, quadruply lensing systems. In the concordance cosmology, we find $H_0 = 71.8^{+3.9}_{-3.3}\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1}$…
We present a cosmographic study designed to test the simplest type of accelerating cosmology: a flat universe with matter and a cosmological constant ($\Lambda$). Hubble series expansions are fit to the SCP Union2.1 supernova data set to…
A new method is proposed to measure the Hubble constant H0 through the mean transmitted flux observed from high redshift quasars. A semi-analytical model for the cosmological-independent volume density distribution function is adopted which…
Since the expansion of the universe was first established by Edwin Hubble and Georges Lemaitre about a century ago, the Hubble constant H0 which measures its rate has been of great interest to astronomers. Besides being interesting in its…
A new method, based on the absorption of very high-energy gamma-rays by the cosmic infrared background, is proposed to constrain the value of the Hubble constant. As this value is both fundamental for cosmology and still not very well…
The Hubble constant ${H}_0$ is a crucial parameter in cosmology. However, different cosmic observations have resulted in varying posterior results for ${H}_0$, leading to what is known as the ${H}_0$ tension. In order to address this issue,…
Recent cosmic microwave background (CMB) measurements over a large range of angular scales have become sensitive enough to provide interesting constraints on cosmological parameters within a restricted class of models. We use the CMB…
We discuss the problems of applying Maximum Likelihood methods to the CMB and how one can make it both efficient and optimal. The solution is a generalised eigenvalue problem that allows virtually no loss of information about the parameter…
Based on the assumption that some apparent properties of the observable universe are accurate at a reasonable level of approximation, a tentative is made to independently derive the values of the baryon density parameter, the Hubble…
The standard model of cosmology, the $\Lambda$CDM model, describes the evolution of the Universe since the Big Bang with just a few parameters, six in its basic form. Despite being the simplest model, direct late-time measurements of the…
For 100 years since galaxies were found to be flying apart from each other, astronomers have been trying to determine how fast. The expansion, characterized by the Hubble constant, H0, is confused locally by peculiar velocities caused by…
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…
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…