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Early dark energy (EDE) that behaves like a cosmological constant at early times (redshifts $z\gtrsim3000$) and then dilutes away like radiation or faster at later times can solve the Hubble tension. In these models, the sound horizon at…

宇宙学与河外天体物理 · 物理学 2019-06-12 Vivian Poulin , Tristan L. Smith , Tanvi Karwal , Marc Kamionkowski

The Hubble tension is investigated taking into account the cosmological look-back time. Specifically, considering a single equation, widely used in standard cosmology, it is possible to recover both values of the Hubble constant $H_0$…

宇宙学与河外天体物理 · 物理学 2023-03-30 Salvatore Capozziello , Giuseppe Sarracino , Alessandro D. A. M. Spallicci

In this work, we obtain measurements of the Hubble constant in the context of modified gravity theories. We set up our theoretical framework by considering viable cosmological $f(R)$ and $f(T)$ models, and we analyzed them through the use…

宇宙学与河外天体物理 · 物理学 2020-05-07 Rocco D'Agostino , Rafael C. Nunes

{{The reappearance of supernova Refsdal with detailed modeling of the lens cluster allows us to measure the time-delay distance,}} which serves as a powerful tool to determine the Hubble constant ($H_0$). We give a…

宇宙学与河外天体物理 · 物理学 2024-05-07 Xiaolei Li , Kai Liao

Using a model-independent analysis method which bases on the Lagrange mean value theorem for obtaining the derivative of the Hubble function, we analyze $H(z)$ parameter data with some restrictive conditions. We find that: (a) the Universe…

广义相对论与量子宇宙学 · 物理学 2025-12-11 Rong-Jia Yang

We show that a minimally extended varying-speed-of-light (meVSL) cosmology can alleviate the Hubble tension through a single parameter, b. This parameter both shortens the sound horizon at the drag epoch and modifies cosmological time…

综合物理 · 物理学 2025-09-12 Seokcheon Lee

The Hubble constant $H_0$ is one of the important cosmological parameters measuring the expansion rate of our universe at present moment. Over the last couple of years, $H_0$ has created an enormous amount of debates interests in the…

宇宙学与河外天体物理 · 物理学 2024-10-29 Supriya Pan , Weiqiang Yang

The cosmic microwave background (CMB) monopole temperature evolves with the inverse of the cosmological scale factor, independent of many cosmological assumptions. With sufficient sensitivity, real-time cosmological observations could thus…

宇宙学与河外天体物理 · 物理学 2020-05-14 Maximilian H. Abitbol , J. Colin Hill , Jens Chluba

We analyse the possibility that our Universe could be described by the model recently proposed by Melia & Shevchuk (2012), where the Hubble scale R_h=c/H is at all times equal to the distance ct that light has travelled since the Big Bang.…

宇宙学与河外天体物理 · 物理学 2012-08-28 Maciej Bilicki , Marina Seikel

We test the theoretical predictions of several cosmological models against different observables to compare the indirect estimates of the current expansion rate of the Universe determined from model fitting with the direct measurements…

宇宙学与河外天体物理 · 物理学 2016-11-09 Vladimir V. Luković , Rocco D'Agostino , Nicola Vittorio

The Hubble parameter H0 still not very well measured. Although the Hubble Key Project, Chandra and WMAP gave good estimates, the uncertainties remain quite large. In this brief report, we suggest an original and independent method to derive…

天体物理学 · 物理学 2009-11-13 A. Barrau , A. Gorecki , J. Grain

We establish a cosmological-model-independent method to extract the apparent magnitude and its derivative at different redshifts from the Pantheon+ type Ia supernova sample, and find that the obtained values deviate clearly from the…

宇宙学与河外天体物理 · 物理学 2024-07-26 Yang Liu , Hongwei Yu , Puxun Wu

Recent observations of Cepheids in the Virgo cluster have bolstered the evidence that supports a Hubble constant in 70-90 km/s/Mpc range. This evidence, by and large, probes the expansion of the Universe within 100 Mpc. We investigate the…

天体物理学 · 物理学 2015-06-24 Xiangdong Shi , Lawrence M. Widrow , L. Jonathan Dursi

We introduce a novel way of measuring $H_0$ from a combination of independent geometrical datasets, with no need of calibration nor of the choice of a cosmological model. We build on the {\it distance duality relation} which sets the ratio…

宇宙学与河外天体物理 · 物理学 2022-06-20 Fabrizio Renzi , Alessandra Silvestri

We explore cosmological implications of a genuinely Weyl invariant (WI) gravitational interaction. The latter reduces to general relativity in a particular conformal frame for which the gravitational coupling and active gravitational masses…

宇宙学与河外天体物理 · 物理学 2022-05-04 Meir Shimon

A value of the Hubble constant has been determined from a comparison of the X-ray properties and Sunyaev-Zel'dovich effect of the distant rich cluster of galaxies CL0016+16. The cluster, as imaged by the ROSAT PSPC, is significantly…

天体物理学 · 物理学 2009-10-30 John P. Hughes , Mark Birkinshaw

We investigate a spatially flat FLRW cosmological model in the framework of modified gravity described by the function \( f(R, L_m) = \alpha R + L_m^\beta + \gamma \), where \( L_m \) is the matter Lagrangian density. The modified Friedmann…

广义相对论与量子宇宙学 · 物理学 2026-02-05 G. K. Goswami , Anirudh Pradhan , Syamala Krishnannair

The discrepancy between the value of the Hubble constant $H_0$ measured from the local distance ladder and from the cosmic microwave background is the most serious challenge to the standard $\Lambda$CDM model. Various models have been…

宇宙学与河外天体物理 · 物理学 2022-10-05 Jian-Ping Hu , F. Y. Wang

We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…

天体物理学 · 物理学 2014-11-18 Daniel G. Figueroa , Licia Verde , Raul Jimenez

Modified theories of gravity encompass a class of $f(R)$-models that seek to elucidate the observed late time accelerated expansion of the universe. In this study, we examine a set of viable $f(R)$ models (Hu-Sawicki: two cases,…

宇宙学与河外天体物理 · 物理学 2023-12-15 Kumar Ravi , Anirban Chatterjee , Biswajit Jana , Abhijit Bandyopadhyay
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