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X-ray observations of galaxy clusters allow us to estimate the gas fraction, and thus the baryon fraction, and its evolution over time. This offers an additional cosmological probe as well as a probe of the gas behaviour in massive halos at…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Hyeon Kim , Raphaël Wicker , Benjamin L'Huillier , Marian Douspis , Laura Salvati , Arman Shafieloo

Most of current cosmological theories are built combining an isotropic and homogeneous manifold with a scale factor that depends on time. If one supposes a hyperconical universe with linear expansion, an inhomogeneous metric can be obtained…

General Relativity and Quantum Cosmology · Physics 2018-10-02 Robert Monjo

We focus on uncertainties in supernova measurements, in particular of individual magnitudes and redshifts, to review to what extent supernovae measurements of the expansion history of the universe are likely to allow us to constrain a…

Astrophysics · Physics 2011-05-12 Lawrence M. Krauss , Katherine Jones-Smith , Dragan Huterer

We use lookback time versus redshift data from galaxy clusters (Capozziello et al., 2004) and passively evolving galaxies (Simon et al., 2005), and apply a bayesian prior on the total age of the Universe based on WMAP measurements, to…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Lado Samushia , Abha Dev , Deepak Jain , Bharat Ratra

We present the cosmological parameters constraints obtained from the combination of galaxy cluster mass function measurements (Vikhlinin et al., 2009a,b) with new cosmological data obtained during last three years: updated measurements of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. A. Burenin , A. A. Vikhlinin

Most cosmological parameter estimations are based on the same set of observations and are therefore not independent. Here, we test the consistency of parameter estimations using a combination of large-scale structure and supernovae data,…

Astrophysics · Physics 2009-11-10 Carolina Odman , Mike Hobson , Anthony Lasenby , Alessandro Melchiorri

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…

General Relativity and Quantum Cosmology · Physics 2019-04-30 Grigoris Panotopoulos , Angel Rincon

We use some of the recently released observational data to test the viability of two classes of minimally coupled scalar field models of quintessence with exponential potentials for which exact solutions of the Einstein equations are known.…

Astrophysics · Physics 2009-11-10 M. Demianski , E. Piedipalumbo , C. Rubano , C. Tortora

In the present work we analyze and compare the information coming from different observational data sets in the context of a sort of f(T) theories. We perform a joint analysis with measurements of the most recent type Ia supernovae (SNe…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Gabriel R. Bengochea

We discuss combined constraints, coming from the cosmic microwave background shift parameter $\mathcal{R}$, baryon acoustic oscillations (BAO) distance parameter $\mathcal{A}$, and from the latest type Ia supernovae data, imposed on…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-11 Tomasz Denkiewicz , Mariusz P. Dabrowski , Hoda Ghodsi , Martin A. Hendry

We perform a global analysis of cosmological observables in generalized cosmologies which depart from $\Lambda$CDM models by allowing non-vanishing curvature $\Omega_k\neq 0$, dark energy with equation of state with $\omega\neq -1$, the…

High Energy Physics - Phenomenology · Physics 2011-06-17 M. C. Gonzalez-Garcia , Michele Maltoni , Jordi Salvado

We consider a very simple toy model for a spatially varying `cosmological constant', where we are inside a spherical bubble (with a given set of cosmological parameters) that is surrounded by a larger region where these parameters are…

Astrophysics · Physics 2009-11-06 P. P. Avelino , J. P. M. de Carvalho , C. J. A. P. Martins

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…

Astrophysics · Physics 2009-11-07 M. Douspis , A. Riazuelo , Y. Zolnierowski , A. Blanchard

The latest improvements in the scale and calibration of Type Ia supernovae catalogues allow us to constrain the specific nature and evolution of dark energy through its effect on the expansion history of the universe. We present the results…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-05 Toby Lovick , Suhail Dhawan , Will Handley

Recently collected SNIa data have been used to address the problem of measuring the cosmological parameters of the universe. Analysed in the framework of homogeneous models, they have yielded, as a primary result, a strictly positive…

Astrophysics · Physics 2007-05-23 Marie-Noëlle Célérier

Widening cracks are appearing in the $\Lambda$CDM model and it is becoming increasingly clear that the standard cosmological model struggles to describe the full expansion history of the Universe as revealed by the Cosmic Microwave…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Alexie Leauthaud , Adam Riess

Full suite of the present day Cosmic Microwave background (CMB) data, when combined with weak prior information on the Hubble constant and the age of the Universe, or the Large-Scale structure, provides strong indication for a non-zero…

Astrophysics · Physics 2007-05-23 D. Pogosyan , J. R. Bond , C. R. Contaldi

Given a class of dark energy models, constraints from one set of cosmic acceleration observables make predictions for other observables. Here we present the allowed ranges for the expansion rate H(z), distances D(z), and the linear growth…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-23 Michael J. Mortonson , Wayne Hu , Dragan Huterer

We measure the current expansion rate of the Universe, Hubble's constant $H_0$, by calibrating the absolute magnitudes of supernovae to distances measured by Baryon Acoustic Oscillations. This `inverse distance ladder' technique provides an…