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Recently Tsallis cosmology has been presented as a novel proposal for alleviating both $H_0$ and $\sigma_8$ tensions. Hence a universe filled with matter and radiation as perfect fluids and considering the Tsallis entropy is confronted…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-23 M. L. Mendoza-Martínez , A. Cervantes-Contreras , J. J. Trejo-Alonso , A. Hernandez-Almada

We present a Bayesian analysis of cosmological parameter constraints from early- and late-universe observations, focusing on the matter density parameter ($\Omega_m$) and the amplitude of matter fluctuations ($\sigma_8$) within the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-13 Manjeet Kunwar , Nabin Bhusal , Manil Khatiwada , Niraj Dhital

We explore the cosmological implications of generalized entropic models within the framework of Gravity-Thermodynamics (GT) approaches. These models, characterized by three or four additional free parameters, are designed to capture…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-06 Udit K. Tyagi , Sandeep Haridasu , Soumen Basak

Assessing the consistency of parameter constraints derived from different cosmological probes is an important way to test the validity of the underlying cosmological model. In an earlier work [Nicola et al., 2017], we computed constraints…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-01 Andrina Nicola , Adam Amara , Alexandre Refregier

Model-independent approaches have gained increasing attention as powerful tools to investigate persistent tensions between cosmological observations and the predictions of $\Lambda$CDM. Notably, recent DESY5 Type Ia Supernovae (SNIa) and…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-04 Arianna Favale , Adrià Gómez-Valent , Marina Migliaccio

We use measurements from the Planck satellite mission and galaxy redshift surveys over the last decade to test three of the basic assumptions of the standard model of cosmology, $\Lambda$CDM: the spatial curvature of the universe, the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-20 Shadab Alam , Shirley Ho , Alessandra Silvestri

We investigate a two-parameter extension of the $\Lambda_{\rm s}$CDM model by allowing variations in the effective number of neutrino species $N_{\rm eff}$ and their total mass $\sum m_\nu$. Our motivation is twofold: (i) to examine whether…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Anita Yadav , Suresh Kumar , Cihad Kibris , Ozgur Akarsu

The recent measurements of Cosmic Microwave Background temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the $\Lambda$CDM cosmological model. However interesting hints of slight…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk

We investigate the cosmological implications of Tsallis entropy in two widely discussed frameworks: the Cai-Kim thermodynamic derivation of the Friedman equations and the Tsallis holographic dark energy (HDE) scenario, considering both the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-06 Pedro M. Ibarbo-Perlaza. , J. Bayron Orjuela-Quintana , Jose L. Palacios-Córdoba , César A. Valenzuela-Toledo

We present a full-fledged analysis of Brans-Dicke cosmology with a cosmological constant and cold dark matter (BD-$\Lambda$CDM for short). We extend the scenarios where the current cosmological value of the BD-field is restricted by the…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-30 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez , Cristian Moreno-Pulido

A generalized mass-to-horizon entropy has recently been proposed as an extension of the Bekenstein-Hawking area law, derived from a modified mass-horizon relation constructed to ensure consistency with the Clausius equation. Within the…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Giuseppe Gaetano Luciano , Andronikos Paliathanasis

We here investigate the observational viability of Nash gravity as an alternative to the standard $\Lambda$CDM cosmology. Based on Nash's embedding theorem, the model introduces orthogonal perturbations via variations in the extrinsic…

General Relativity and Quantum Cosmology · Physics 2026-01-15 Abraão J. S. Capistrano , Emanuelly Silva , Rafael C. Nunes , Orlando Luongo

We combine new Cosmic Microwave Background (CMB) data from Planck with Baryon Acoustic Oscillation (BAO) data to constrain the Brans-Dicke (BD) theory, in which the gravitational constant $G$ evolves with time. Observations of type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-19 Ji-Xia Li , Feng-Quan Wu , Yi-Chao Li , Yan Gong , Xue-Lei Chen

We study Planck 2015 cosmic microwave background (CMB) anisotropy data using the energy density inhomogeneity power spectrum generated by quantum fluctuations during an early epoch of inflation in the non-flat $\Lambda$CDM model. Unlike…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Junpei Ooba , Bharat Ratra , Naoshi Sugiyama

We use six tilted spatially-flat and untilted non-flat dark energy cosmological models in analyses of South Pole Telescope polarization (SPTpol) cosmic microwave background (CMB) data, alone and in combination with Planck 2015 CMB data and…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-10 Chan-Gyung Park , Bharat Ratra

We study the performance of three pairs of tilted $\Lambda$CDM cosmological models, two pairs allowing for non-flat spatial hypersurfaces with CMB temperature and polarization power spectrum data (P18) from Planck, P18 lensing (lensing),…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-29 Javier de Cruz Perez , Chan-Gyung Park , Bharat Ratra

Non-extensive Tsallis thermostatistics is a widespread paradigm to describe large-scale gravitational systems. In this work we use Tsallis Cosmology to study thermodynamic gravity and derive modified Friedmann equations. We show that…

General Relativity and Quantum Cosmology · Physics 2025-03-25 Giuseppe Gaetano Luciano , Jaume Gine

The standard model of cosmology, {\Lambda}CDM, is the simplest model that matches the current observations, but it relies on two hypothetical components, to wit, dark matter and dark energy. Future galaxy surveys and cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-13 Cyrille Doux , Mariana Penna-Lima , Sandro D. P. Vitenti , Julien Tréguer , Eric Aubourg , Ken Ganga

The DESI collaboration, combining their Baryon Acoustic Oscillation (BAO) data with cosmic microwave background (CMB) anisotropy and supernovae data, have found significant indication against the $\Lambda$CDM cosmology. This can also be…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-09 Marina Cortês , Andrew R Liddle

We investigate a phenomenological extension of the standard $\Lambda$CDM framework, the $\Omega_1\Omega_2$-$\Lambda$CDM model, in which the total energy density of the universe is expanded in powers of $1+z$. This parameterization recovers…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Suresh Kumar