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In order to investigate the origin of the ongoing tension between the amplitude of matter fluctuations measured by weak lensing experiments at low redshifts and the value inferred from the cosmic microwave background anisotropies, we…

The dynamics of the Universe are revised using high-redshift data from gamma-ray bursts to constrain cosmographic parameters by means of model-independent techniques. Considering samples from four gamma-ray burst correlations and two…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-13 Orlando Luongo , Marco Muccino

Yes, for a wide range of cosmological models ($\Lambda$CDM, non-interacting $w_z$CDM or models with possible interactions between dark energy and dark matter, in either phantom or non-phantom regimes). In the recent past there have been…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-17 Archita Bhattacharyya , Ujjaini Alam , Kanhaiya Lal Pandey , Subinoy Das , Supratik Pal

A recently proposed generalized entropy by Luciano and Saridakis extends the standard Boltzmann-Gibbs and Bekenstein-Hawking framework through a microscopically motivated construction involving two independent entropic exponents. When…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-21 Matías Leizerovich , Susana J. Landau , Giuseppe Gaetano Luciano , Andreas Papatriantafyllou , Emmanuel N. Saridakis

We construct cosmological models consisting of large numbers of identical, regularly spaced masses. These models do not rely on any averaging procedures, or on the existence of a global Friedmann-Robertson-Walker (FRW) background. They are…

General Relativity and Quantum Cosmology · Physics 2015-05-18 Timothy Clifton

The $\Lambda$CDM model is the current standard model in cosmology thanks to its ability to reproduce the observations. Its first observational evidence appeared from the type Ia supernovae (SNIa) Hubble diagram. However, there has been some…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-01 Isaac Tutusaus , Brahim Lamine , Alain Blanchard

Motivated by statistical inference problems in high-dimensional time series data analysis, we first derive non-asymptotic error bounds for Gaussian approximations of sums of high-dimensional dependent random vectors on hyper-rectangles,…

Statistics Theory · Mathematics 2024-06-05 Jinyuan Chang , Xiaohui Chen , Mingcong Wu

We wish to investigate whether there is an extension to the base $\Lambda$CDM cosmology that can resolve the tension between the Planck observation of the cosmic microwave background anisotropies and the local measurement of the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-28 Rui-Yun Guo , Jing-Fei Zhang , Xin Zhang

Many statistical models in cosmology can be simulated forwards but have intractable likelihood functions. Likelihood-free inference methods allow us to perform Bayesian inference from these models using only forward simulations, free from…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Justin Alsing , Benjamin Wandelt , Stephen Feeney

We test a class of holographic models for the very early universe against cosmological observations and find that they are competitive to the standard $\Lambda$CDM model of cosmology. These models are based on three dimensional perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 Niayesh Afshordi , Claudio Coriano , Luigi Delle Rose , Elizabeth Gould , Kostas Skenderis

We study the dynamical behaviour of gauge-invariant linear perturbations in spherically symmetric dust cosmologies including a cosmological constant. In contrast to spatially homogeneous FLRW models, the reduced degree of spatial symmetry…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 Sven Meyer , Matthias Bartelmann

In this work, we investigate the cosmological dynamics of an anisotropic Universe within the framework of $f(R,T)$ gravity by incorporating pressureless dark matter and the dark energy models. The analysis is carried out in a Bianchi type-I…

General Relativity and Quantum Cosmology · Physics 2026-05-13 S. H. Shekh , N. Myrzakulov , Anirudh Pradhan , M. Zeyauddin

The present paper deals with the dynamics of spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model with a time varying cosmological constant $\Lambda$ where $\Lambda$ evolves with the cosmic time (t) through the…

General Relativity and Quantum Cosmology · Physics 2022-10-19 Chingtham Sonia , S. Surendra Singh

Recent measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI DR2), combined with data from the cosmic microwave background (CMB) and Type Ia supernovae (SNe), challenge the $\Lambda$-Cold Dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-16 Agripino Sousa-Neto , Carlos Bengaly , Javier E. Gonzalez , Jailson Alcaniz

We review observational tests for the homogeneity of the Universe on large scales. Redshift and peculiar velocity surveys, radio sources, the X-Ray Background, the Lyman-$\alpha$ forest and the Cosmic Microwave Background are used to set…

Astrophysics · Physics 2007-05-23 Ofer Lahav

In this article, we study a flat homogeneous FLRW model in Lyra geometry which is described by a time-dependent displacement vector. We consider an appropriate parametrization of the energy density of scalar field $ \rho_\phi $ in terms of…

General Relativity and Quantum Cosmology · Physics 2023-04-04 J. K. Singh , Shaily , Shri Ram , Joao R. L. Santos , Jéferson A. S. Fortunato

Recently, in [1], we presented the first combined non-parametric reconstruction of the three time-dependent functions that capture departures from the standard cosmological model, $\Lambda$CDM, in the expansion history and gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Marco Raveri , Levon Pogosian , Matteo Martinelli , Kazuya Koyama , Alessandra Silvestri , Gong-Bo Zhao

We study the cosmology of a specific class of nonlocal model of modified gravity, the so-called Deser-Woodard (DW) model, modifying the Einstein-Hilbert action by a term $\sim R f(\Box^{-1}R)$, where $f$ is a free function. Choosing $f$ so…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-18 Luca Amendola , Yves Dirian , Henrik Nersisyan , Sohyun Park

We demonstrate a model-independent method of estimating qualitative dynamics of an accelerating universe from observations of distant type Ia supernovae. Our method is based on the luminosity-distance function, optimized to fit observed…

Astrophysics · Physics 2009-11-10 Marek Szydlowski , Wojciech Czaja

We present the first suite of cosmological N-body simulations that simultaneously include the effects of two different and theoretically independent extensions of the standard $\Lambda$CDM cosmological scenario - namely an $f(R)$ theory of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Marco Baldi , Francisco Villaescusa-Navarro , Matteo Viel , Ewald Puchwein , Volker Springel , Lauro Moscardini