Topic
Deceleration parameter
About: Deceleration parameter is a research topic. Over the lifetime, 1776 publications have been published within this topic receiving 89440 citations.
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TL;DR: In this article , a non-flat Friedmann-Robertson-Walker universe with a pressureless dark matter (DM) and Barrow holographic dark energy (BHDE) whose IR cutoff is the apparent horizon was studied.
13 citations
TL;DR: In this article, the authors apply the type Ia supernovae union dataset and the baryon acoustic oscillations data at z = 0.2 and z =0.35 to constrain variable Chaplygin gas (VCG) model as the unification of dark matter and dark energy.
Abstract: We apply the type Ia supernovae union dataset and the baryon acoustic oscillations data at z = 0.2 and z = 0.35 to constrain variable Chaplygin gas (VCG) model as the unification of dark matter and dark energy. It is shown that the confidence levels for VCG model parameters are $B_{s}=0.075^{+0.016}_{-0.013}(1\sigma)$ $^{+0.026}_{-0.020}(2\sigma)$, $n=1.30^{+0.46}_{-0.49}(1\sigma)$ $^{+0.74}_{-0.81}(2\sigma)$. And it indicates that the values of transition redshift and current deceleration parameter are: $z_{T}=0.74^{+0.05}_{-0.05}(1\sigma)$, $q_{0}=-0.54^{+0.07}_{-0.07}(1\sigma)$. In addition, we plot the evolution trajectory of the VCG model in the statefinder parameter r–s plane and show the discrimination between this scenario and other dark energy models.
12 citations
TL;DR: In this article, the authors studied the possible existing anisotropy in the acceleration expansion by using the full sample of Union2 data, and they found that the maximum accelerating expansion direction is $(l,b)=(314+20^{\circ])+20 √ √ 12 √ 13 √ 14 √ 15 √ 16 √ 17 √ 18 √ 19 √ 20 √ 22 √ 23 √ 24 √ 27 √ 28 √ 29 √ 30 √ 32 √ 34 √ 35 √ 36 �
Abstract: In this paper we study the possibly existing anisotropy in the acceleration expansion by use of the full sample of Union2 data. Using the hemisphere comparison method to search for a preferred direction, we take the deceleration parameter q0 as the diagnostic to quantify the anisotropy level in the wCDM model. We find that the maximum accelerating expansion direction is $(l,b)=(314_{+20^{\circ}}^{\circ-13^{\circ}},28_{+11^{\circ}}^{\circ-33^{\circ}})$,with the maximum anisotropy level of $\delta q_{0,max}/\bar{q}_0=0.79_{+0.27}^{-0.28}$, and that the anisotropy is more prominent when only low redshift data ($z\leq0.2$) are used. We also discuss this issue in the $CPL$ parameterized model, showing a similar result.
12 citations
TL;DR: In this article, the authors examined non-linear EOS with a general nonlinear term in the energy density, which is explored in the presence of perfect fluid and dark energy too.
Abstract: We have investigated general Bianchi type I cosmological models which containing a perfect fluid and dark energy with time varying G and Λ that have been presented. The perfect fluid is taken to be one obeying the equation of state parameter, i.e., p=ωρ; whereas the dark energy density is considered to be either modified polytropic or the Chaplygin gas. Cosmological models admitting both power-law which is explored in the presence of perfect fluid and dark energy too. We reconstruct gravitational parameter G, cosmological term Λ, critical density ρc, density parameter Ω, cosmological constant density parameter ΩΛ and deceleration parameter q for different equation of state. The present study will examine non-linear EOS with a general nonlinear term in the energy density.
12 citations
TL;DR: In this article, the authors analyzed holographic principle inspired dark energy models, namely, holographic dark energy (HDE) model, Tsallis HDE model, and the R e ´ nyi HEDE model by using the statefinder parameter diagnostic.
12 citations