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We investigate in detail some popular cosmological models in light of the latest observational data, including the Union2.1 supernovae compilation, the baryon acoustic oscillation measurements from the WiggleZ Dark Energy Survey, the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Ke Shi , Yongfeng Huang , Tan Lu

We investigate the potential of using cosmic voids as a probe to constrain cosmological parameters through the gravitational lensing effect of the cosmic microwave background (CMB) and make predictions for the next generation surveys. By…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-19 Teeraparb Chantavat , Utane Sawangwit , P. M. Sutter , Benjamin D. Wandelt

Type Ia Supernovae, calibrated by classical distance ladder methods, can be used, in conjunction with galaxy survey two-point correlation functions, to empirically determine the size of the sound horizon $r_{\rm s}$. Assumption of the…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-26 Kevin Aylor , Mackenzie Joy , Lloyd Knox , Marius Millea , Srinivasan Raghunathan , W. L. Kimmy Wu

We analyze Lemaitre-Tolman-Bondi models in presence of the cosmological constant \Lambda through the classical Weierstrass criterion. Precisely, we show that the Weierstrass approach allows us to classify the dynamics of these inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Ivana Bochicchio , Salvatore Capozziello , Ettore Laserra

We place tight constraints on the redshift-averaged, effective value of the equation of state of dark energy, w, using only the absolute ages of Galactic stars and the observed position of the first peak in the angular power spectrum of the…

Astrophysics · Physics 2011-07-18 Raul Jimenez , Licia Verde , Tommaso Treu , Daniel Stern

Extensions to the $\Lambda\textrm{CDM}$ model prior to recombination can modify the growth of perturbations around radiation-matter equality, leaving a distinct signature in the matter power spectrum. Upcoming large-scale structure surveys…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Raphaël Kou , Antony Lewis

We propose to use relative galaxy ages as a means of constraining cosmological parameters. By measuring the age difference between two ensembles of old galaxies at somewhat different redshifts, one could determine the derivative of redshift…

Astrophysics · Physics 2009-11-06 Raul Jimenez , Abraham Loeb

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"…

General Physics · Physics 2013-06-04 Julio A. Gonzalo , Manuel Alfonseca

Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Amr A. El-Zant , Waleed El Hanafy , Alexey Golovnev

The age of the universe is obtained in a subset of Cardassian models by using WMAP data. Cardassian expansion is a modification to the Friedmann equation that allows the universe to be flat, matter dominated, and accelerating, without a…

Astrophysics · Physics 2016-08-30 Christopher Savage , Noriyuki Sugiyama , Katherine Freese

The concordance (LambdaCDM) model reproduces the main current cosmological observations assuming the validity of general relativity at all scales and epochs, the presence of cold dark matter, and of a cosmological constant, equivalent to a…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-08 Guido Risaliti , Elisabeta Lusso

We present the final nine-year maps and basic results from the WMAP mission. We provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are…

We have reanalyzed the age of the universe problem under the assumption that the lower limit on the age of the globular clusters is 11Gyr, as predicted by the recent Hipparcos data. We find that the globular cluster and the expansion ages…

Astrophysics · Physics 2007-05-23 Murat Özer

Observational evidence consistently shows that the universe is spatially flat and undergoes Lorentzian time dilation as a function of redshift. In combination, such discoveries suggest that a Minkowskian description of cosmology might be…

General Physics · Physics 2024-10-14 Artur Novais , A. L. B. Ribeiro

We study the main cosmological properties of the agegraphic dark energy model at the expansion and perturbation levels. Initially, using the latest cosmological data we implement a joint likelihood analysis in order to constrain the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-28 M. Malekjani , S. Basilakos , A. Mehrabi , Z. Davari , M. Rezaei

We combine information on cosmological parameters from cluster abundances, CMB primordial anisotropies and the IRAS 1.2 Jy galaxy redshift survey. We take as free parameters the present values of the total matter density of the universe,…

Astrophysics · Physics 2009-10-31 S. L. Bridle , V. R. Eke , O. Lahav , A. N. Lasenby , M. P. Hobson , S. Cole , C. S. Frenk , J. P. Henry

We investigate the cosmic age problem associated with the old high-$z$ quasar APM 08279 + 5255 and the oldest globular cluster M 107, both being difficult to accommodate in $\Lambda$CDM model. By evaluating the age of the Universe in a…

Astrophysics · Physics 2008-11-10 Shuang Wang , Yang Zhang

Ever refined cosmological measurements have established the $\Lambda$CDM concordance model, with the key cosmological parameters being determined to percent-level precision today. This allows us to make explicit predictions for the spectral…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-23 Jens Chluba

The next generation near- and mid-infrared Galactic surveys will yield a large number of new highly obscured star clusters. Detailed characterization of these new objects with spectroscopy is time-consuming. Diagnostic tools that will be…

Astrophysics of Galaxies · Physics 2015-05-14 Yuri Beletsky , Giovanni Carraro , Valentin D. Ivanov

Current observations suggest that our Universe is not incompatible with a small positive spatial curvature that can be associated with rest frames having a "closed" standard topology. We examine a toy model generalisation of the…

General Relativity and Quantum Cosmology · Physics 2018-07-09 Sebastián Nájera , Roberto A. Sussman