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相关论文: Growth Index in the $\gamma\delta$CDM model

200 篇论文

Two different realistic $F(R)$ modified gravity models are considered in the framework of the Friedmann-Lemetre-Robertson-Walker universe. The parameters of these two models are adjusted to reach coherence with the most recent and accurate…

广义相对论与量子宇宙学 · 物理学 2015-06-12 Antonio Jesús López-Revelles

In this work, we have considered a minimally modified gravity theory that effectively reproduces VCDM-like behavior to investigate its cosmological implications. The model parameters are constrained using a combination of CC, RSD, DESI BAO…

宇宙学与河外天体物理 · 物理学 2026-03-31 Sai Swagat Mishra , Soumya Kanta Bhoi , P. K. Sahoo

The $\Gamma$ growth model is an effective parameterization employed across various scientific disciplines and scales to depict growth. It has been demonstrated that the cosmic star formation rate density (CSFRD) can also be described…

We investigate the properties of the FLRW flat cosmological models in which the vacuum energy density evolves with time, $\Lambda(t)$. Using different versions of the $\Lambda(t)$ model, namely quantum field vacuum, power series vacuum and…

宇宙学与河外天体物理 · 物理学 2015-05-13 S. Basilakos , M. Plionis , J. Sola

We study the evolution of linear perturbations in metric f(R) models of gravity and identify a potentially observable characteristic scale-dependent pattern in the behavior of cosmological structures. While at the background level viable…

天体物理学 · 物理学 2014-11-18 Levon Pogosian , Alessandra Silvestri

We present cosmological parameter constraints from the SFI++ galaxy peculiar velocity survey, the largest galaxy peculiar velocity sample to date. The analysis is performed by using the gridding method developed in Abate et al. (2008). We…

宇宙学与河外天体物理 · 物理学 2015-05-13 Alexandra Abate , Pirin Erdogdu

This is the third 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. Our data set…

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

We obtain the exact analytic form of the growth index at present epoch ($a=1$) in a flat universe with the cosmological constant ({\it i.e.} the dark energy with its equation of state $\omega_{de} = -1$). For the cosmological constant, we…

宇宙学与河外天体物理 · 物理学 2013-12-16 Seokcheon Lee , Kin-Wang Ng

Probes of cosmic expansion constitute the main basis for arguments to support or refute a possible apparent acceleration due to different expansion rates in the universe as described by inhomogeneous cosmological models. We present in this…

宇宙学与河外天体物理 · 物理学 2015-06-16 Mustapha Ishak , Austin Peel , M. A. Troxel

We use Luminous Red Galaxies from the Sloan Digital Sky Survey II to test the cosmological structure growth in two alternatives to the standard LCDM+GR cosmological model. We compare observed three-dimensional clustering in SDSS DR7 with…

The $\Lambda$CDM model successfully explains a wide range of cosmological observations; however, persistent discrepancies most notably the $H_0$ tension between early and late time measurements challenge its completeness. No proposed…

宇宙学与河外天体物理 · 物理学 2026-03-31 Upala Mukhopadhyay , Purba Mukherjee , Alexandre Tkatchenko

We investigate the matter density perturbation $\delta_m$ and power spectrum $P(k)$ in the running vacuum model (RVM) with the cosmological constant being a function of the Hubble parameter, given by $\Lambda = \Lambda_0 + 6 \sigma H H_0+…

宇宙学与河外天体物理 · 物理学 2016-11-09 Chao-Qiang Geng , Chung-Chi Lee

The LCDM cosmological model assumes the existence of a small cosmological constant in order to explain the observed accelerating cosmic expansion. Despite the dramatic improvement of the quality of cosmological data during the last decade…

宇宙学与河外天体物理 · 物理学 2015-05-18 L. Perivolaropoulos

We analyze Dark Energy Survey (DES) data to constrain a cosmological model where a subset of parameters -- focusing on $\Omega_m$ -- are split into versions associated with structure growth (e.g. $\Omega_m^{\rm grow}$) and expansion history…

In this study, we investigate the growth of structures within the Deser-Woodard nonlocal theory and extend it to various bouncing cosmology scenarios. Our findings show that the observable structure growth rate, $f\sigma_8$, in a…

广义相对论与量子宇宙学 · 物理学 2023-05-10 D. Jackson , R. Bufalo

In this paper we place observational constraints on the well-known $\gamma$-gravity $f(R)$ model using the latest cosmological data, namely we use the latest growth rate, Cosmic Microwave Background, Baryon Acoustic Oscillations, Supernovae…

宇宙学与河外天体物理 · 物理学 2018-07-17 Clara Álvarez Luna , Spyros Basilakos , Savvas Nesseris

We present a new test of gravitational physics by comparing the growth rate of cosmic structure measured around voids with that measured around galaxies in the same large-scale structure dataset, the low-redshift 6-degree Field Galaxy…

宇宙学与河外天体物理 · 物理学 2017-04-12 Ixandra Achitouv , Chris Blake , Paul Carter , Jun Koda , Florian Beutler

We focus on the class of cosmological models with a time-evolving vacuum energy density of the form $\rho_\Lambda=C_0+C_1 H+C_2 H^2$, where $H$ is the Hubble rate. Higher powers of $H$ could be important for the early inflationary epoch,…

宇宙学与河外天体物理 · 物理学 2015-03-13 Adria Gomez-Valent , Joan Sola

We disclose the effects of an extra longitudinal degree of freedom on the evolution of perturbations in the framework of mimetic gravity. We consider a flat Friedmann-Robertson-Walker (FRW) background and explore the linear perturbations by…

广义相对论与量子宇宙学 · 物理学 2022-08-02 Bita Farsi , Ahmad Sheykhi

Considering a well-motivated $f(R)$ modified-gravity model, in which an exponential function of the curvature is included, in this paper we implement a statistical data analysis to set constraints on the parameters of the model, taking into…

宇宙学与河外天体物理 · 物理学 2025-05-01 Mario A. Acero , A. Oliveros