arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.1259astro-ph.CO
收藏

用当前观测约束扰动早期暗能量

Constraining Perturbative Early Dark Energy with Current Observations

Ujjaini Alam

备注：
12 pages, 5 figures, references updated, accepted for publication in ApJ
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

在这项工作中，我们研究了一类早期的暗能量（EDE）模型，其中，与标准DE模型不同，大量的DE存在于物质主导的时代，自洽包括DE扰动。我们的分析表明，边缘化的非DE参数，如$Omega_m, H_0, n_s$，目前的CMB观测单独可以约束的比例因子从早期DE到晚期DE到$a_t \geq 0.44$和过渡宽度的过渡到$Delta_t \leq 0.37$。如果我们允许$H_0 < 60$ km/s/Mpc，那么目前的状态方程对$w_0 \leq -0.6$的约束有点弱。与其他观测，如超新星，HST和SDSS LRG一起，限制更严格- $w_0 \leq -0.9, a_t \leq 0.19, Δ_t \leq 0.21$。EDE模型的状态方程的演变，因此接近$Λ$ CDM在低红移。不正确地假设DE扰动可以忽略不计导致状态方程参数的不同约束，从而突出了自洽包括DE扰动的必要性。如果我们允许空间曲率是一个自由参数，那么对于CMB+其他观测，约束被放松到$w_0 \leq -0.77, a_t \leq 0.35, Δ_t \leq 0.35$和$-0.014 < Ω_κ < 0.031$。对于扰动的EDE模型，$σ_8$（$σ_8 \geq 0.59$）的$2σ$下限远低于$Λ$ CDM（$σ_8 \geq 0.72$），从而提高了有趣的可能性，区分EDE从$Λ$ CDM使用未来的观测，如晕质量函数或Sunyaev-Zeldovich功率谱。

英文摘要：

In this work, we study a class of early dark energy (EDE) models, in which, unlike in standard DE models, a substantial amount of DE exists in the matter-dominated era, self-consistently including DE perturbations. Our analysis shows that, marginalizing over the non DE parameters such as $Omega_m, H_0, n_s$, current CMB observations alone can constrain the scale factor of transition from early DE to late time DE to $a_t \geq 0.44$ and width of transition to $Delta_t \leq 0.37$. The equation of state at present is somewhat weakly constrained to $w_0 \leq -0.6$, if we allow $H_0 < 60$ km/s/Mpc. Taken together with other observations, such as supernovae, HST, and SDSS LRGs, the constraints are tighter-- $w_0 \leq -0.9, a_t \leq 0.19, Δ_t \leq 0.21$. The evolution of the equation of state for EDE models is thus close to $Λ$CDM at low redshifts. Incorrectly assuming DE perturbations to be negligible leads to different constraints on the equation of state parameters, thus highlighting the necessity of self-consistently including DE perturbations in the analysis. If we allow the spatial curvature to be a free parameter, then the constraints are relaxed to $w_0 \leq -0.77, a_t \leq 0.35, Δ_t \leq 0.35$ with $-0.014 < Ω_κ < 0.031$ for CMB+other observations. For perturbed EDE models, the $2σ$ lower limit on $σ_8$ ($σ_8 \geq 0.59$) is much lower than that in $Λ$CDM ($σ_8 \geq 0.72$), thus raising the interesting possibility of discriminating EDE from $Λ$CDM using future observations such as halo mass functions or the Sunyaev-Zeldovich power spectrum.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑