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Dark energy (DE) models with many free parameters are often considered excessive, as constraining all parameters poses a significant challenge. While such models offer greater flexibility to probe the DE sector in more detail. With the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Hanyu Cheng , Supriya Pan , Eleonora Di Valentino

We perform a cosmological parameter analysis of the 75 square degree CTIO lensing survey in conjunction with CMB and Type Ia supernovae data. For Lambda CDM cosmologies, we find that the amplitude of the power spectrum at low redshift is…

Astrophysics · Physics 2008-11-26 Mike Jarvis , Bhuvnesh Jain , Gary Bernstein , Derek Dolney

I show how to compute the nonlinear power spectrum across the entire $w(z)$ dynamical dark energy model space. Using synthetic $\Lambda$CDM data, I train a neural ordinary differential equation (ODE) to infer the evolution of the nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-25 Peter L. Taylor

We discuss an extension of the Coyote emulator to predict non-linear matter power spectra of dark energy (DE) models with a scale factor dependent equation of state of the form w = w_0 + ( 1 - a )w_a . The extension is based on the mapping…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 L. Casarini , S. A. Bonometto , E. Tessarotto , P. -S. Corasaniti

Stability analysis of interacting dark energy models generally divides its parameters space into two regions: (i) $w_x \geq -1$ and $\xi \geq 0$ and (ii) $w_x \leq -1$ and $\xi \leq 0$, where $w_x$ is the dark energy equation of state and…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-14 Weiqiang Yang , Supriya Pan , David F. Mota

Models including an energy transfer from CDM to DE are widely considered in the literature, namely to allow DE a significant high-z density. Strongly Coupled cosmologies assume a much larger coupling between DE and CDM, together with the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-26 S. A. Bonometto , M. Mezzetti , I. Musco , R. Mainini , A. V. Maccio'

In this second paper we present the first Nbody cosmological simulations of strongly coupled Dark Energy models (SCDEW), a class of models that alleviates theoretical issues related to the nature of dark energy. SCDEW models assume a strong…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-09 Andrea V. Macciò , Roberto Mainini , Camilla Penzo , Silvio A. Bonometto

We perform a general test of the $\Lambda{\rm CDM}$ and $w {\rm CDM}$ cosmological models by comparing constraints on the geometry of the expansion history to those on the growth of structure. Specifically, we split the total matter energy…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Uendert Andrade , Dhayaa Anbajagane , Rodrigo von Marttens , Dragan Huterer , Jailson Alcaniz

In this paper, we test the dark matter-dark energy interacting cosmological model with a dynamic equation of state $w_{DE}(z)=w_{0}+w_{1}z/(1+z)$, using type Ia supernovae (SNe Ia), Hubble parameter data, baryonic acoustic oscillation (BAO)…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-16 J. S. Wang , F. Y. Wang

We examine how lensing tomography with the bispectrum and power spectrum can constrain cosmological parameters and the equation of state of dark energy. Our analysis uses the full information at the two- and three-point level from angular…

Astrophysics · Physics 2010-04-06 Masahiro Takada , Bhuvnesh Jain

The conceptual difficulties associated with a cosmological constant have led to the investigation of alternative models in which the equation of state parameter, $w=p/\rho$, of the dark energy evolves with time. We show that combining the…

Astrophysics · Physics 2007-05-23 H. K. Jassal , J. S. Bagla , T. Padmanabhan

We apply a new non-parametric Bayesian method for reconstructing the evolution history of the equation-of-state $w$ of dark energy, based on applying a correlated prior for $w(z)$, to a collection of cosmological data. We combine the latest…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-20 Gong-Bo Zhao , Robert G. Crittenden , Levon Pogosian , Xinmin Zhang

Cosmology has entered an era of unprecedented precision, yet increasing accuracy has revealed cracks in the standard $\Lambda$CDM paradigm. Although the model remains highly successful when confronted with individual datasets, joint…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-06 Eleonora Di Valentino

We derive multiple constraints on dark energy and compare dynamical dark energy models with a time-varying equation of state ($w_0 w_a$CDM) versus a cosmological constant model ($\Lambda$CDM). We use Baryon Acoustic Oscillation (BAO) from…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-24 Mustapha Ishak , Leonel Medina-Varela

Constraining simultaneously the Dark Energy(DE) equation of state and the curvature of the Universe is difficult due to strong degeneracies. To circumvent this problem when analyzing data it is usual to assume flatness to constrain DE, or…

Astrophysics · Physics 2009-06-23 J. -M. Virey , D. Talon-Esmieu , A. Ealet , P. Taxil , A. Tilquin

I review the observational prospects to constrain the equation of state parameter of dark energy and I discuss the potential of future imaging and redshift surveys. Bayesian model selection is used to address the question of the level of…

Astrophysics · Physics 2007-05-23 Roberto Trotta

We find that if we live at the center of an inhomogeneity with total density contrast of roughly 0.1, dark energy is not a cosmological constant at 95% confidence level. Observational constraints on the equation of state of dark energy, w,…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-17 Valerio Marra , Mikko Pääkkönen , Wessel Valkenburg

We show that any accelerating Friedmann-Robertson-Walker (FRW) cosmology with equation of state w < -1/3 (and therefore not only a de Sitter stage with w =-1) exhibits three-dimensional conformal symmetry on future constant-time…

High Energy Physics - Theory · Physics 2015-06-17 A. Kehagias , A. Riotto

Accurately measuring the masses of white dwarf stars is crucial in many astrophysical contexts (e.g., asteroseismology and cosmochronology). These masses are most commonly determined by fitting a model atmosphere to an observed spectrum;…

Solar and Stellar Astrophysics · Physics 2016-10-10 T. A. Gomez , M. H. Montgomery , T. Nagayama , D. P. Kilcrease , D. E. Winget

Baryonic Acoustic Oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI), in combination with Cosmic Microwave Background (CMB) data and Type Ia Supernovae (SN) luminosity distances, suggests a dynamical evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 João Rebouças , Diogo H. F. de Souza , Kunhao Zhong , Vivian Miranda , Rogerio Rosenfeld