Related papers: Status of Cosmology
In a historical perspective, compact solutions of Einstein's equations, including the cosmological constant and the curvature terms, are obtained, starting from two recent observational estimates of the Hubble's parameter (H0) and the "age"…
In this paper, motivated from the fact that a de Sitter cosmological boundary corresponds to a positive cosmological constant, we consider time variable cosmological constants, dubbed {\it horizon cosmological constants}. The horizon…
We present a joint analysis of the Planck cosmic microwave background (CMB) and Baryon Oscillation Spectroscopic Survey (BOSS) final data releases. A key novelty of our study is the use of a new full-shape (FS) likelihood for the…
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…
We compare several well-known cosmological dark energy models using observational data coming both from type Ia supernovae and from Hubble parameter measurements. First we use supernovae data to determine the free parameters of each model…
For decades, the determination of the mean density of matter(Omega_M) has been tied to the distribution of light. This has led to a ``bias,'' perhaps as large as a factor of 2, in determining a key cosmological parameter. Recent…
The Hubble constant $H_0$ is the value of the cosmic expansion rate at one time (the present), and cannot be adjusted successfully without taking into account the entire expansion history and cosmology. We outline some conditions, that if…
Our cosmology contains Big Bang relic fluctuations by a loss of time-translation symmetry on a Hubble time scale. The contribution to the vacuum is identified with dynamical dark energy $\Lambda\simeq \alpha_p\Lambda_0$ by an IR coupling…
We use the age measurements of 114 old astrophysical objects (OAO) in the redshift range $0\lesssim z\lesssim 8$ to explore the Hubble tension. The age of the Universe at any $z$ is inversely proportional to the Hubble constant, $H_0$, so…
We study constraints that anticipated DEEP survey galaxy counts versus redshift data will place on cosmological model parameters in models with and without a constant or time-variable cosmological constant $\Lambda$. This data will result…
We compare the latest observations of Cosmic Microwave Background (CMB) Anisotropies with the theoretical predictions of the standard scenario of structure formation. Assuming a primordial power spectrum of adiabatic perturbations we found…
We present here a phenomenological cosmological model under perfect fluid distribution with a stiff equation of state $p=\rho$. The erstwhile cosmological constant is assumed to be a time dependent variable, i.e., $\Lambda = \Lambda(t)$ in…
We present a study of the baryonic fraction in galaxy clusters aimed at constraining the cosmological parameters Omega_m, Omega_Lambda and the ratio between the pressure and density of the ``dark'' energy, w. We use results on the…
We advance the viewpoint that only relevant modes of the vacuum fluctuations, namely, with wavelengths conditioned by the size, homogeneity, geometry and topology of the Universe, do contribute into the cosmological constant. A formula is…
In this work, we present independent determinations of cosmological parameters and new constraints on $f(T)$ cosmologies, employing two new catalogs related to HII galaxy Hubble and CMB distance priors, along with the local standard…
We introduce a holographic dark energy model that incorporates the first-order approximate Kaniadaski entropy, utilizing the Hubble horizon, $1/H$, as the infrared cutoff. We investigate the cosmological evolution within this framework. The…
Under four assumptions such that 1) Einstein's theory of gravity is correct, 2) existence of foliation by geodesic slicing, 3) the trace of the extrinsic curvature, $K$, is negative at the present time in observed region, that is, the…
The CMB anisotropy depends sensitively upon the slope and amplitude of primordial density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} We report…
We use higher-redshift gamma-ray burst (GRB), HII starburst galaxy (HIIG), and quasar angular size (QSO-AS) measurements to constrain six spatially flat and non-flat cosmological models. These three sets of cosmological constraints are…
We report estimates of the cosmological parameters $\Omega_m$ and $\Omega_{\Lambda}$ obtained using supernovae (SNe) associated with gamma-ray bursts (GRBs) at redshifts up to 0.606. Eight high-fidelity GRB-SNe with well-sampled light…