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For dynamical dark energy with the barotropic equation of state we determine the mean values of parameters and their confidence ranges together with other cosmological parameters on the basis of different combined datasets. The used…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-13 O. Sergijenko

Cosmological constraints on the total neutrino mass, $\sum m_\nu$, are strongly shaped by assumptions about the dark-energy equation of state due to the well-known degeneracy between massive neutrinos and late-time cosmic acceleration. In…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Gowri S Nair , Amlan Chakraborty , Luca Amendola , Subinoy Das

It has been theorized that Dynamical Dark Energy (DDE) could be a possible solution to the Hubble tension. To avoid the degeneracy between the Hubble parameter $H_0$ and the sound horizon scale $r_d$, in this article we use their…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-02 Denitsa Staicova

In this paper, we combine the the latest observational data, including the WMAP five-year data (WMAP5), the baryon acoustic oscillations (BAO) and type Ia supernovae (SN) "union" compilation, and use the Markov Chain Monte Carlo method to…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-11 Hong Li , Jun-Qing Xia

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

Reconstructing the evolution history of the dark energy equation of state parameter $w(z)$ directly from observational data is highly valuable in cosmology, since it contains substantial clues in understanding the nature of the accelerated…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Zhi-E Liu , Hao-Ran Yu , Tong-Jie Zhang , Yan-Ke Tang

Assuming that the Universe at higher redshifts (z \sim 4 and beyond) is consistent with LCDM model as constrained by the Planck measurements, we reanalyze the low redshift cosmological data to reconstruct the Hubble parameter as a function…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-18 Koushik Dutta , Ruchika , Anirban Roy , Anjan A. Sen , M. M. Sheikh-Jabbari

We use Hubble parameter versus redshift data from Stern, et al(2010) and Gazta\~{n}aga, et al (2009) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are consistent…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-12 Yun Chen , Bharat Ratra

We present improved constraints on an interacting vacuum model using updated astronomical observations including the first data release from Planck. We consider a model with one dimensionless parameter, $\alpha$, describing the interaction…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Yuting Wang , David Wands , Gong-Bo Zhao , Lixin Xu

We investigate how the properties of dark energy affect the cosmological measurements of neutrino mass and extra relativistic degrees of freedom. We limit ourselves to the most basic extensions of $\Lambda$ cold dark matter (CDM) model,…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 Ming-Ming Zhao , Yun-He Li , Jing-Fei Zhang , Xin Zhang

We investigate a four-parameter entropic dark energy model in a spatially curved FLRW universe, based on a generalized entropy-area relation at the apparent horizon. While the proposed entropy function captures a broad class of…

General Relativity and Quantum Cosmology · Physics 2025-11-21 Davood Momeni

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

Current observational bounds on dark energy depend on assumptions about the curvature of the universe. We present a simple and efficient method for incorporating constraints from CMB anisotropy data, and use it to derive constraints on…

Astrophysics · Physics 2010-04-06 Yun Wang , Pia Mukherjee

Allowing for greater low-redshift flexibility through parametrizations such as CPL can lead to apparent deviations from $\Lambda$CDM, with the latter lying at roughly the $2\sigma$ level from the best-fit model. This motivates an…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 Md. Wali Hossain

We put constraints on dark energy properties using the PADE parameterisation, and compare it to the same constraints using Chevalier-Polarski-Linder (CPL) and $\Lambda$CDM, at both the background and the perturbation levels. The dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-09 Mehdi Rezaei , Mohammad Malekjani , Spyros Basilakos , Ahmad Mehrabi , David F. Mota

We present updated observational constraints on the spatially flat $\phi$CDM model, where dark energy is described by a minimally coupled scalar field $\phi$ with an inverse power-law potential $V=V_0 \phi^{-\alpha}$. Using Planck 2018 CMB…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Chan-Gyung Park , Bharat Ratra

One of the main challenges of modern cosmology is to investigate the nature of dark energy in our Universe. The properties of such a component are normally summarised as a perfect fluid with a (potentially) time-dependent equation-of-state…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-19 J. Alberto Vazquez , M. Bridges , M. P. Hobson , A. N. Lasenby

Cosmological constraints are usually derived under the assumption of a $6$ parameters $\Lambda$-CDM theoretical framework or simple one-parameter extensions. In this paper we present, for the first time, cosmological constraints in a…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk

Recent DESI results indicate a strong preference for dynamical dark energy (DE) when baryon acoustic oscillation (BAO) measurements are combined with supernovae (SNe) and cosmic microwave background (CMB) data using the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-26 Shubham Barua , Shantanu Desai

Most parametrizations for dark energy involve the equation of state $w$ of the dark energy. In this work, we choose the pressure of the dark energy to parametrize. As $p = constant$ essentially gives a cosmological constant, we use the…

Astrophysics · Physics 2008-11-26 A. A. Sen