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In a model of the late-time cosmic acceleration within the framework of generalized Proca theories, there exists a de Sitter attractor preceded by the dark energy equation of state $w_{\rm DE}=-1-s$, where $s$ is a positive constant. We run…

宇宙学与河外天体物理 · 物理学 2017-07-05 Antonio De Felice , Lavinia Heisenberg , Shinji Tsujikawa

The possibility of linking inflation and late cosmic accelerated expansion using the $\alpha$-attractor models has received increasing attention due to their physical motivation. In the early universe, $\alpha$-attractors provide an…

宇宙学与河外天体物理 · 物理学 2018-08-21 Carlos García-García , Eric V. Linder , Pilar Ruíz-Lapuente , Miguel Zumalacárregui

We use the latest Type Ia supernovae sample Pantheon+ to explore new physics on cosmic scales. Specifically, in light of this new sample, we constrain the interacting dark energy and Hu-Sawicki $f(R)$ gravity models and employ the…

宇宙学与河外天体物理 · 物理学 2022-09-20 Deng Wang

Unified Dark Matter models describe Dark Matter and Dark Energy as a single entity which is, in the simplest case, embodied in a perfect barotropic fluid. It is a well-established fact that small adiabatic perturbations of Unified Dark…

宇宙学与河外天体物理 · 物理学 2010-05-28 Oliver F. Piattella

We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06<z<0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can…

天体物理学 · 物理学 2008-11-26 R. W. Schmidt , S. W. Allen

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…

宇宙学与河外天体物理 · 物理学 2026-02-20 Suresh Kumar

We investigate a scalar field dark energy model (i.e., $\phi$CDM model) with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., $V(\phi)\propto {\phi}^{-\alpha}$ ($\alpha>0$). We find that the sum of…

宇宙学与河外天体物理 · 物理学 2015-12-14 Yun Chen , Lixin Xu

We show that in clustering dark energy models the growth index of linear matter perturbations, $\gamma$, can be much lower than in $\Lambda$CDM or smooth quintessence models and present a strong variation with redshift. We find that the…

宇宙学与河外天体物理 · 物理学 2014-07-08 Ronaldo C. Batista

The motivation of the present work is to reconstruct a dark energy model through the {\it dimensionless dark energy function} $X(z)$, which is the dark energy density in units of its present value. In this paper, we have shown that a scalar…

广义相对论与量子宇宙学 · 物理学 2017-02-01 Abdulla Al Mamon , Kazuharu Bamba , Sudipta Das

We perform a joint likelihood analysis of the power spectra of the 2dF Galaxy Redshift Survey (2dFGRS) and the cosmic microwave background (CMB) anisotropies under the assumptions that the initial fluctuations were adiabatic, Gaussian and…

We investigate the model of dark matter-dark energy (DM-DE) interaction with coupling strength proportional to the multiplication of dark sector densities with different power indices $Q = \gamma \rho_{\rm c}^{\alpha} \rho_{\rm d}^{\beta}$.…

宇宙学与河外天体物理 · 物理学 2020-08-26 Gong Cheng , Yin-Zhe Ma , Fengquan Wu , Jiajun Zhang , Xuelei Chen

This is the fourth of a series of papers in which we derive simultaneous constraints on cosmological parameters and X-ray scaling relations using observations of the growth of massive, X-ray flux-selected galaxy clusters. Here we examine…

宇宙学与河外天体物理 · 物理学 2015-05-14 Adam Mantz , Steven W. Allen , David Rapetti

We propose in this paper a new model for describing the unification of dark energy and dark matter. This new model is a further generalization of the generalized Chaplygin gas (GCG) model, thus dubbed new generalized Chaplygin gas (NGCG)…

天体物理学 · 物理学 2009-11-10 Xin Zhang , Feng-Quan Wu , Jingfei Zhang

We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…

We consider asymptotically stable scalar-tensor dark energy (DE) models for which the equation of state parameter $w_{DE}$ tends to zero in the past. The viable models are of the phantom type today, however this phantomness is milder than…

天体物理学 · 物理学 2009-06-23 Radouane Gannouji , David Polarski

It has been recently shown that tachyonic chameleon model of dark energy in which tachyon scalar field non-minimally coupled to the matter admits stable scaling attractor solution that could give rise to the late-time accelerated expansion…

广义相对论与量子宇宙学 · 物理学 2018-03-21 A. Banijamali , S. Bellucci , B. Fazlpour , M. Solbi

We reconstruct dark energy properties from two complementary supernova datasets -- the newly released Gold+HST sample and SNLS. The results obtained are consistent with standard $\Lambda$CDM model within $2\sigma$ error bars although the…

天体物理学 · 物理学 2010-10-27 Ujjaini Alam , Varun Sahni , Alexei A. Starobinsky

We studied the cosmological constraints on the Galileon gravity obtained from observational data of the growth rate of matter density perturbations, the supernovae Ia (SN Ia), the cosmic microwave background (CMB), and baryon acoustic…

宇宙学与河外天体物理 · 物理学 2012-07-03 Koichi Hirano , Zen Komiya , Hisato Shirai

We propose a new class of cosmological unified dark sector models called "{\em Generalized Logotropic Models}". They depend on a free parameter $n$. The original logotropic model [P.H. Chavanis, Eur. Phys. J. Plus {\bf 130}, 130 (2015)] is…

广义相对论与量子宇宙学 · 物理学 2022-02-17 Hachemi B. Benaoum , Pierre-Henri Chavanis , Hernando Quevedo

An open or hyperbolic Friedmann-Robertson-Walker spacetime dominated by tachyonic dark matter can exhibit an ``inflected'' expansion -- initially decelerating, later accelerating -- similar but not identical to that of now-standard…

宇宙学与河外天体物理 · 物理学 2024-03-22 Samuel H. Kramer , Ian H. Redmount