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We investigate observational constraints on cosmological parameters combining 15 measurements of the transversal BAO scale (obtained free of any fiducial cosmology) with Planck-CMB data to explore the parametric space of some cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-10 Rafael C. Nunes , Santosh K. Yadav , J. F. Jesus , Armando Bernui

We propose a phenomenological unified model for dark matter and dark energy based on an equation of state parameter $w$ that scales with the $\arctan$ of the redshift. The free parameters of the model are three constants: $\Omega_{b0}$,…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-17 R. R. Cuzinatto , L. G. Medeiros , E. M. de Morais

In the context of a theory of minimally modified gravity called VCDM, one can realize any cosmological behavior at the level of the homogeneous and isotropic background without introducing fatal instabilities for perturbations. Therefore,…

General Relativity and Quantum Cosmology · Physics 2025-11-24 Simran Arora , Antonio De Felice , Shinji Mukohyama

We constrain two non-flat time-evolving dark energy cosmological models by using Hubble parameter data, Type Ia supernova apparent magnitude measurements, and baryonic acoustic oscillation peak length scale observations. The inclusion of…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Omer Farooq , Data Mania , Bharat Ratra

We explore an extension of the $\Lambda$CDM model in which the pressure $p$ of the dark energy (DE) fluid evolves with the expansion of the Universe, expressed as a function of the scale factor $a$. The corresponding energy density $\rho$…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-22 Hanyu Cheng , Eleonora Di Valentino , Luis A. Escamilla , Anjan A. Sen , Luca Visinelli

Bulk dark energy properties are determined by the redshift evolution of its pressure-to-density ratio, $w_{de}(z)$. An experimental goal is to decide if the dark energy is dynamical, as in the quintessence (and phantom) models treated here.…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Zhiqi Huang , J. Richard Bond , Lev Kofman

We use all available baryon acoustic oscillation distance measurements and Hubble parameter data to constrain the cosmological constant $\Lambda$, dynamical dark energy, and spatial curvature in simple cosmological models. We find that the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-19 Joseph Ryan , Sanket Doshi , Bharat Ratra

We use a variant of principal component analysis to investigate the possible temporal evolution of the dark energy equation of state, w(z). We constrain w(z) in multiple redshift bins, utilizing the most recent data from Type Ia supernovae,…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Paolo Serra , Asantha Cooray , Daniel E. Holz , Alessandro Melchiorri , Stefania Pandolfi , Devdeep Sarkar

We constrain the scalar field dark energy model with an inverse power-law potential, i.e., $V(\phi)\propto {\phi}^{-\alpha}$ ($\alpha>0$), from a set of recent cosmological observations by compiling an updated sample of Hubble parameter…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-10 Yun Chen , Chao-Qiang Geng , Shuo Cao , Yu-Mei Huang , Zong-Hong Zhu

We present a comprehensive Bayesian analysis of the Hubble constant within the framework of Physics-Informed Neural Networks (PINNs), focusing on the standard $\Lambda$CDM model and its dynamical dark energy extensions described by the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-05 Muhammad Yarahmadi , Amin Salehi

In the paper, we consider two models in which dark energy is coupled with either dust matter or dark matter, and discuss the conditions that allow more time for structure formation to take place at high redshifts. These models are expected…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-08 Shulei Cao , Tong-Jie Zhang , Xinya Wang , Tingting Zhang

Recent measurements of baryon acoustic oscillations (BAO) from the Dark Energy Spectroscopic Instrument (DESI) have been interpreted to suggest that dark energy may be evolving. In this work, we examine how prior choices affect such…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-17 Michael W. Toomey , Gabriele Montefalcone , Evan McDonough , Katherine Freese

The dark energy that appears to produce the accelerating expansion of the universe can be characterized by an equation of state p=w\rho with w<-1/3. A number of observational tests have been proposed to study the value or redshift…

Astrophysics · Physics 2009-11-07 Jens Kujat , Angela M. Linn , Robert J. Scherrer , David H. Weinberg

We examine in some detail the influence of the systematics in different data sets including type Ia supernova sample, baryon acoustic oscillation data and the cosmic microwave background information on the fitting results of the…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-21 Yungui Gong , Bin Wang , Rong-gen Cai

We place observational constraints on an FLRW cosmological model in $f(R,L_m)$ gravity with a specific deceleration parameter that depends on the scale factor. This form of the deceleration parameter has been discussed by authors in several…

General Relativity and Quantum Cosmology · Physics 2024-12-30 Aroonkumar Beesham

We introduce a new parametrization for the dark energy, led by the same idea to the linear expansion of the equation of state in scale factor $a$ and in redshift $z$, which diverges neither in the past nor future and contains the same…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-01 Ozgur Akarsu , Tekin Dereli , J. Alberto Vazquez

We show that the abundance and redshift distribution ($dN/dz$) of galaxy clusters in future high--yield cluster surveys, combined with the spatial power spectrum ($P_c(k)$) of the same clusters, can place significant constraints on the…

Astrophysics · Physics 2008-11-26 Sheng Wang , Justin Khoury , Zoltan Haiman , Morgan May

We study dynamical dark energy models that allow for general late time behaviour while admitting non-phantom dynamics at early times, including thawing, scaling$+$thawing, and effective fluid extensions. Using current cosmological data, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-24 Sk. Sohail , Sonej Alam , Md. Wali Hossain

In this work we study the consequences of allowing non pressureless dark matter when determining dark energy constraints. We show that present-day dark energy constraints from low-redshift probes are extremely degraded when allowing this…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 Isaac Tutusaus , Brahim Lamine , Alain Blanchard

Recent analyses have shown that a dynamic dark energy modeled by the CPL parameterization of the dark energy equation of state (EoS) can ease constraints on the total neutrino mass compared to the standard $\Lambda$CDM model. This helps…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Gabriel Rodrigues , Rayff de Souza , Jamerson Rodrigues , Jailson Alcaniz