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The determination of the Hubble constant has been a central goal in observational astrophysics for nearly 100 years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-14 C. L. Bennett , D. Larson , J. L. Weiland , G. Hinshaw

The matter content of the Universe is strongly inhomogeneous on small scales. Motivated by this fact, we consider a model of the Universe that has regularly spaced discrete masses, rather than a continuous fluid. The optical properties of…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Timothy Clifton , Pedro G. Ferreira

We study the clustering of the mass distribution in COBE-normalized open and flat CDM models using large N-body simulations. With an age of the universe of 14 Gyr (12 Gyr) for the flat (open) models and a baryon density fixed by…

Astrophysics · Physics 2015-06-24 Shaun Cole , David H. Weinberg , Carlos S. Frenk , Bharat Ratra

The status of the standard cosmological model, also known as "LCDM" is described. With some simple assumptions, this model fits a wide range of data, with just six (or seven) free parameters. One should be skeptical about this claim, since…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-05 Douglas Scott

An intriguing discrepancy emerging in the concordance model of cosmology is the tension between the locally measured value of the Hubble rate, and the 'global' value inferred from the cosmic microwave background (CMB). This could be due to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Vinicius C. Busti , Chris Clarkson , Marina Seikel

The age of the Universe depends on both the present-day Hubble Constant and on the history of cosmic expansion. For decelerating cosmologies such as Omega_m= 1, the dimensionless product H_0,t_0<1 and modestly high values of the Hubble…

Astrophysics · Physics 2016-08-30 John L. Tonry , The High-Z Supernova Search Team

We consider a varieties of quintessence scalar field models in a homogeneous and isotropic geometry of the universe with zero spatial curvature aiming to provide stringent constraints using a series of cosmological data sets, namely, the…

General Relativity and Quantum Cosmology · Physics 2019-07-24 Weiqiang Yang , M. Shahalam , Barun Pal , Supriya Pan , Anzhong Wang

Departures of the energy spectrum of the cosmic microwave background (CMB) from a perfect blackbody probe a fundamental property of the universe -- its thermal history. Current upper limits, dating back some 25 years, limit such spectral…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-01 A. Kogut , M. H. Abitbol , J. Chluba , J. Delabrouille , D. Fixsen , J. C. Hill , S. P. Patil , A. Rotti

The properties of nearby galaxy clusters limit the range of cosmological parameters consistent with our universe. We describe the limits which arise from studies of the intracluster medium (ICM) mass fraction fICM and consideration of the…

Astrophysics · Physics 2016-11-03 Joseph J. Mohr , Zoltan Haiman , Gilbert P. Holder

We show how estimates of parameters characterizing inflation-based theories of structure formation localized over the past year when large scale structure (LSS) information from galaxy and cluster surveys was combined with the rapidly…

Recently funded satellites will map the cosmic microwave background radiation with unprecedented sensitivities and angular resolutions. Assuming only primordial adiabatic scalar and tensor perturbations, we evaluate how accurately…

Astrophysics · Physics 2009-10-28 Arthur Kosowsky , Marc Kamionkowski , Gerard Jungman , David N. Spergel

At variance from 2H, 3He and 4He abundances, 7Li abundance data yield an extra constraint to cosmological parameters, in top of those deriving from CMB, BAO, SNIa or H0 data. This constraint, often disregarded, would favor smaller $\Omega_b…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-29 G. La Vacca , A. Valotti , S. A. Bonometto

This article briefly summarizes the increasingly precise observational estimates of the cosmological parameters. After three years on the stump, the Lambda-CDM model is still the leading candidate. Although the Universe is expanding, our…

Astrophysics · Physics 2007-05-23 Charles H. Lineweaver

Recently, Sahni, Shafielo o & Starobinsky (2014) combined two independent measurements of $H(z)$ from BAO data with the value of the Hubble constant $H_0 = H(z=0)$, in order to test the cosmological constant hypothesis by means of an…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-21 Xuheng Ding , Marek Biesiada , Shuo Cao , Zhengxiang Li , Zong-Hong Zhu

The current enthusiam to measure fluctuations in the CMB power spectrum at angular scales between 0.1 and 1 degree is largely motivated by the expectation that CMB determinations of cosmological parameters will be of unprecedented…

Astrophysics · Physics 2007-05-23 C. H. Lineweaver

In this article, we introduce an innovative parametric representation of the Hubble parameter, providing a model-independent means to explore the dynamics of an accelerating cosmos. The model's parameters are rigorously constrained through…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-16 M. Koussour , N. Myrzakulov , M. K. M. Ali

The measured luminosity distances of Type Ia supernovae (SNe Ia) as a function of redshift have shown that the expansion of the Universe is currently accelerating, probably due to the presence of repulsive dark energy such as Einstein's…

Astrophysics · Physics 2017-08-23 A. V. Filippenko

The time evolution of the number density of galaxy clusters and their mass and temperature functions are used to constrain cosmological parameters in the spatially flat dark matter models containing a fraction of hot particles (massive…

Astrophysics · Physics 2009-11-07 N. A. Arhipova , T. Kahniashvili , V. N. Lukash

Next year we will celebrate 100 years of the cosmological term, $\Lambda$, in Einstein's gravitational field equations, also 50 years since the cosmological constant problem was first formulated by Zeldovich, and almost about two decades of…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Joan Sola

We investigate a relativistic cosmological model with background rotation, sourced by a non-perfect fluid with anisotropic stress. A modified version of the CLASS Boltzmann code is employed to perform Monte Carlo Markov Chain analyses…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Micol Benetti , David A. Cook , Saulo Carneiro