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The sum of cosmic neutrino masses can be measured cosmologically, as the sub-eV particles behave as `hot' dark matter whose main effect is to suppress the clustering of matter compared to a universe with the same amount of purely cold dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-05 Helen Shao , Jahmour J. Givans , Jo Dunkley , Mathew Madhavacheril , Frank Qu , Gerrit Farren , Blake Sherwin

We show that the 32 $H(z)$ data from cosmic chronometers have overestimated uncertainties and make use of a Bayesian method to correct and reduce it. We then use the corrected data to constrain flat $\Lambda$CDM and O$\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-10 Nícolas Romeiro Kvint , José Fernando de Jesus , Saulo Henrique Pereira

We compile 41 $H(z)$ data from literature and use them to constrain O$\Lambda$CDM and flat $\Lambda$CDM parameters. We show that the available $H(z)$ suffers from uncertainties overestimation and propose a Bayesian method to reduce them. As…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 J. F. Jesus , T. M. Gregório , F. Andrade-Oliveira , R. Valentim , C. A. O. Matos

In the context of a homogeneous and isotropic universe, we consider the degeneracy condition at the background level between two scenarios in which processes out of equilibrium are possible; this consideration allows us to deviate from the…

General Relativity and Quantum Cosmology · Physics 2025-03-05 Gilberto Aguilar-Pérez , Ana A. Avilez-López , Miguel Cruz

A huge amount of good quality astrophysical data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision…

Astrophysics · Physics 2009-06-23 S. Capozziello

Bayesian statistics and Markov Chain Monte Carlo (MCMC) algorithms have found their place in the field of Cosmology. They have become important mathematical and numerical tools, especially in parameter estimation and model comparison. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-02 Luis E. Padilla , Luis O. Tellez , Luis A. Escamilla , J. Alberto Vazquez

The Cosmological Constant Lambda, a concept introduced by Einstein in 1917, has been with us ever since in different variants and incarnations, including the broader concept of Dark Energy. Current observations are consistent with a value…

Popular Physics · Physics 2020-12-30 Ofer Lahav

The accelerated expansion of the Universe is one of the main discoveries of the past decades, indicating the presence of an unknown component: the dark energy. Evidence of its presence is being gathered by a succession of observational…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-13 V. Motta , Miguel A. García-Aspeitia , A. Hernández-Almada , J. Magaña , Tomás Verdugo

Causal dissipative model is a plausible choice to explain the late accelerated epoch of universe. At the same time $\Lambda$CDM is considered to be standard model to explain the cosmological data corresponding to the late evolution of the…

General Relativity and Quantum Cosmology · Physics 2021-09-10 V Mohammed Shareef , ND Jerin Mohan , Titus K Mathew

Several attempts to solve the cosmological constant problem, which concerns the value of the cosmological constant being extremely smaller than the Standard Model mass scales, have introduced a scalar field with a very flat potential that…

High Energy Physics - Phenomenology · Physics 2024-04-10 Wen Yin

Any theory invoked to explain cosmic acceleration predicts consistency relations between the expansion history, structure growth, and all related observables. Currently there exist high-quality measurements of the expansion history from…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 R. Ali Vanderveld , Michael J. Mortonson , Wayne Hu , Tim Eifler

One of the most tantalizing results from the WMAP experiment is the suggestion that the power at large scales is anomalously low when compared to the prediction of the ``standard'' Lambda-CDM model. The same anomaly, although with somewhat…

Astrophysics · Physics 2009-11-10 Anastasia Niarchou , Andrew H. Jaffe , Levon Pogosian

The $\Lambda$CDM model has long served as the cornerstone of modern cosmology, offering an elegant and successful framework for interpreting a wide range of cosmological observations. However, the rise of high-precision datasets has…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Manish Yadav , Archana Dixit , Anirudh Pradhan , M S Barak

Recent results regarding dark energy are mutually inconsistent under the $\Lambda$CDM cosmological model, hinting at the possibility of undiscovered physics. However, the currently accepted cosmological parameters come from a joint…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-08 Charles L. Steinhardt , Preston Phillips , Radoslaw Wojtak

The observational evidence for the acceleration of the universe demonstrates that canonical theories of gravitation and particle physics are incomplete, if not incorrect. A new generation of astronomical facilities will shortly be able to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 C. J. A. P. Martins

A huge amount of good quality data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision Cosmology. Despite…

General Relativity and Quantum Cosmology · Physics 2008-12-02 S. Capozziello

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

The application of Bayesian methods in cosmology and astrophysics has flourished over the past decade, spurred by data sets of increasing size and complexity. In many respects, Bayesian methods have proven to be vastly superior to more…

Astrophysics · Physics 2009-06-23 Roberto Trotta

While cold dark matter is widely supported by a range of cosmological observations, it encounters several difficulties at smaller scales. These issues have prompted the investigation of various alternative dark matter candidates, leaving…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-23 Jian-Qi Liu , Yan-Hong Yao , Yan Su , Jia-Wei Wu

Bayesian model averaging is a procedure to obtain parameter constraints that account for the uncertainty about the correct cosmological model. We use recent cosmological observations and Bayesian model averaging to derive tight limits on…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-07 M. Vardanyan , R. Trotta , J. Silk
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