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Models of cosmic inflation generically predict a weak but potentially detectable amount of primordial non-Gaussianity (PNG), which can be used to obtain insights into the degrees of freedom during inflation and their interactions. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-05 Anton Chudaykin , Mikhail M. Ivanov , Oliver H. E. Philcox

We provide preliminary quantitative evidence that a new solution to averaging the observed inhomogeneous structure of matter in the universe [gr-qc/0702082, arxiv:0709.0732], may lead to an observationally viable cosmology without exotic…

Astrophysics · Physics 2008-11-26 Ben M. Leith , S. C. Cindy Ng , David L. Wiltshire

To solve some problems of celestial mechanics and astrophysics, three new models of an elliptical galaxy (EG) have been created, which are in good agreement with modern understanding of the structure of such galaxies. Based on these models,…

Astrophysics of Galaxies · Physics 2023-01-20 S. A. Gasanov

Higgs inflation has received a remarkable attention in the last few years due to its simplicity and predictive power. The key point of this model is the nonminimal coupling to gravity in unitary gauge. As such, this theory is in fact a…

General Relativity and Quantum Cosmology · Physics 2014-08-27 Sandrine Schlogel , Massimiliano Rinaldi , Francois Staelens , Andre Fuzfa

General Yang-Mills symmetry and Yang-Mills gravity in inertial frames presents a possible avenue for understanding dark energy phenomenon in terms of the extremely small baryon charges of protons and neutrons. General gauge transformations…

High Energy Physics - Phenomenology · Physics 2022-10-03 Jong-Ping Hsu , Leonardo Hsu

We consider a nonsingular deflationary cosmological model with decaying vacuum energy density in universes of arbitrary spatial curvature. Irrespective of the value of $k$, the models are characterized by an arbitrary time scale $H_I^{-1}$…

Astrophysics · Physics 2009-10-28 J. A. S. Lima , M. Trodden

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…

Astrophysics · Physics 2008-11-26 S. Ettori , P. Tozzi , P. Rosati

Standard cosmology poses a number of important questions. Apart from its singular origin, it possesses early and late accelerating phases required to account for observations. The vacuum energy has been considered as a possible way to…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-25 Saulo Carneiro , Reza Tavakol

In the past years 'quintessence' models have been considered which can produce the accelerated expansion in the universe suggested by recent astronomical observations. One of the key differences between quintessence and a cosmological…

Astrophysics · Physics 2014-10-13 Rachel Bean , Steen H. Hansen , Alessandro Melchiorri

The possibility of the "invisible" axion being cold dark matter relies on the acceptable estimates of the current axion energy density. The estimate depends on the nature of QCD phase transition at a few hundred MeV and the evolution of the…

High Energy Physics - Phenomenology · Physics 2018-04-26 Jihn E. Kim , Se-Jin Kim , Soonkeon Nam

Previous work has related the Galactic Bar to structure in the local stellar velocity distribution. Here we show that the Bar also influences the spatial gradients of the velocity vector via the Oort constants. By numerical integration of…

Astrophysics · Physics 2009-11-13 I. Minchev , J. Nordhaus , A. C. Quillen

The amount of deuterium relative to hydrogen (D/H) in clouds with close to primordial abundance seen at high redshift in the spectra of distant quasars currently provides the best estimate of the baryonic density of the Universe. The first…

Astrophysics · Physics 2009-10-28 Antoinette Songaila , E. Joseph Wampler , Lennox L. Cowie

Recent measurements of the D(p,$\gamma)^3$He, nuclear reaction cross-section and of the neutron lifetime, along with the reevaluation of the cosmological baryon abundance from cosmic microwave background (CMB) analysis, call for an update…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-17 Cyril Pitrou , Alain Coc , Jean-Philippe Uzan , Elisabeth Vangioni

We use Pantheon Type Ia supernova (SN Ia) apparent magnitude, DES-3yr binned SN Ia apparent magnitude, Hubble parameter, and baryon acoustic oscillation measurements to constrain six spatially flat and non-flat cosmological models. These…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Shulei Cao , Joseph Ryan , Bharat Ratra

Measurements of the cosmological density parameter Omega using techniques that exploit the gravity-induced motions of galaxies constrain, in linear perturbation theory, the degenerate parameter combination beta = Omega^{0.6}/b, where the…

Astrophysics · Physics 2011-08-23 Andreas A. Berlind , Vijay K. Narayanan , David H. Weinberg

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of \ell in the…

Experimental evidence over a number of recent years has shown the density parameter of the universe omega converging to the critical value of 1, which defines a flat, Euclidean universe. No such calculations have defined a critical value…

General Physics · Physics 2013-06-20 Peter Rowlands

Standard cosmological analyses typically treat galaxy formation and cosmological parameter inference as decoupled problems, relying on population-level statistics such as clustering, lensing, or halo abundances. However, classical studies…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-05 Kito Liao , Francisco Villaescusa-Navarro , Romain Teyssier , Natalí S. M. de Santi

We measure the cosmological matter density by observing the positions of baryon acoustic oscillations in the clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We jointly analyse the main galaxies and LRGs in the SDSS DR5…

We show that a class of Affleck--Dine baryogenesis directly relates the observed mass density of baryons, \Omega_{B}, to that of dark matter, \Omega_{DM}. In this scenario, the ratio of baryon to dark matter mass density is solely…

High Energy Physics - Phenomenology · Physics 2015-06-25 Masaaki Fujii , T. Yanagida