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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

Despite the remarkable success of the $\Lambda$Cold Dark Matter ($\Lambda$CDM) cosmological model, a growing discrepancy has emerged (currently measured at the level of $\sim 4-6 \sigma$) between the value of the Hubble constant $H_0$…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-07 Nils Schöneberg , Guillermo Franco Abellán , Andrea Pérez Sánchez , Samuel J. Witte , Vivian Poulin , Julien Lesgourgues

The Hubble tension can be addressed by modifying the sound horizon ($r_s$) before recombination, triggering interest in $r_s$-free early-universe estimates of the Hubble constant, $H_0$. Constraints on $H_0$ from an $r_s$-free analysis of…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-30 Tristan L. Smith , Vivian Poulin , Théo Simon

The observed discrepancy of the Hubble parameter measurements in the local universe with the cosmic microwave background (CMB) data may indicate a new physics. It is vital to test the alternative models that reconcile the Hubble tension…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-03 Hossein Moshafi , Shant Baghram , Nima Khosravi

Motivated by the current status of the cosmological observations and significant tensions in the estimated values of some key parameters assuming the standard $\Lambda$CDM model, we propose a simple but radical phenomenological emergent…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-14 Xiaolei Li , Arman Shafieloo

Hubble tension is a problem in one-dimensional (1D) posteriors, since local $H_0$ determinations are only sensitive to a single parameter. Projected 1D posteriors for $\Lambda$CDM cosmological parameters become more non-Gaussian with…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-06 Eoin Ó Colgáin , Saeed Pourojaghi , M. M. Sheikh-Jabbari , Darragh Sherwin

The ages of the oldest stellar objects in our galaxy provide an independent test of the current cosmological model as they give a lower limit to the age of the Universe. Recent accurate parallaxes by the Gaia space mission, accurate…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-01 Raul Jimenez , Andrea Cimatti , Licia Verde , Michele Moresco , Benjamin Wandelt

We review the current status of Early Dark Energy (EDE) models proposed to resolve the "Hubble tension", the discrepancy between "direct" measurements of the current expansion rate of the Universe and "indirect measurements" for which the…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-12 Vivian Poulin , Tristan L. Smith , Tanvi Karwal

The Hubble-Lemaitre tension is currently one of the most important questions in cosmology. Most of the focus so far has been on reconciling the Hubble constant value inferred from detailed cosmic microwave background measurement with that…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-29 Kylar L. Greene , Francis-Yan Cyr-Racine

We investigate a modified cosmological model aimed at addressing the Hubble tension, considering revised dynamics in the late Universe. The model introduces a parameter $c$ affecting the evolution equations, motivated by a modified Poisson…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-13 Luis A. Escamilla , Donatella Fiorucci , Giovanni Montani , Eleonora Di Valentino

We present a Bayesian comparative analysis of five cosmological models: $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, $\phi$CDM (with scalar-field dark energy), and an interacting dark energy scenario (the $\xi$-index model), to investigate dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Zhuoming Zhang , Tengpeng Xu , Yun Chen

Current cosmological data exhibit a tension between inferences of the Hubble constant, $H_0$, derived from early and late-universe measurements. One proposed solution is to introduce a new component in the early universe, which initially…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 J. Colin Hill , Evan McDonough , Michael W. Toomey , Stephon Alexander

This paper is based on two insights: (1) that general relativity alone does not specify how much of the matter density contributes to the source term in Friedmann's equation, and how much contributes as the source of the gravitational…

General Relativity and Quantum Cosmology · Physics 2024-04-23 Richard J. Cook

We have studied how local density perturbations could reconcile the Hubble tension. We reproduced a local void through a perturbed FLRW metric with a potential $\Phi$ which depends on both time and space. This method allowed us to obtain a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 Marco San Martín , Carlos Rubio

One of the problem revealed recently in cosmology is a so-called Hubble tension (HT), which is the difference between values of the present Hubble constant, measured by observation of the universe at redshift $z \lesssim 1$, and by…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-18 G. S. Bisnovatyi-Kogan

We demonstrate that Type Ia supernovae (SNe Ia) observations impose the critical constraint for resolving the Hubble tension through late-time expansion modifications. Applying the Fisher-bias optimization framework to cosmic chronometers…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-10 Zhihuan Zhou , Zhuang Miao , Sheng Bi , Chaoqian Ai , Hongchao Zhang

One approach to reconciling local measurements of a high expansion rate with observations of acoustic oscillations in the CMB and galaxy clustering (the "Hubble tension") is to introduce additional contributions to the $\Lambda$CDM model…

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

The rate at which the universe is expanding today is a fundamental parameter in cosmology which governs our understanding of structure formation and dark energy. However, current measurements of the Hubble constant, $H_0$, show a…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-02 Carlos A. P. Bengaly , Chris Clarkson , Roy Maartens

We present a determination of the Hubble constant from the joint, free-form analysis of 8 strongly, quadruply lensing systems. In the concordance cosmology, we find $H_0 = 71.8^{+3.9}_{-3.3}\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1}$…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-22 Philipp Denzel , Jonathan P. Coles , Prasenjit Saha , Liliya L. R. Williams

The tension between the value of the Hubble constant $H_0$ determined from local supernovae data and the one inferred from the cosmic microwave background based on the $\Lambda$CDM cosmological model may indicate the need for new physics.…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-18 Alejandro Perez , Daniel Sudarsky , Edward Wilson-Ewing
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