Accuracy of the growth index in the presence of dark energy perturbations
Accuracy of the growth index in the presence of dark energy perturbations
复制标题
存在暗能量扰动时生长指数的准确性
DOI：
10.1103/physrevd.92.023013
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发表时间：
2015
影响因子：
5
通讯作者：
Domenico Sapone
中科院分区：
文献类型：
--
作者：
S. Nesseris;Domenico Sapone
我们提出了物质密度扰动演化的解析解，该模型具有恒定的暗能量状态方程 $w$，但适当考虑了暗能量扰动的影响。我们考虑两种情况，第一种情况是扰动的声速为零 $c_s^2=0$ ，一般情况是 $0 10 H_0$ 或等效的 $k/h>0.0033 \textrm{Mpc}^{-1}$ 。我们还估计了增长指数 $\gamma(z)$ 的修正，通常用于参数化增长率。我们发现，DE 扰动引起的这些修正会影响 $3\%$ 水平的增长指数 $\gamma$。我们还将增长指数的新表达式与文献中已有的其他表达式进行比较，我们发现后者不如我们在这里提出的准确。因此，我们的分析计算是必要的，因为对即将到来的巡天约束的基本参数的理论预测需要尽可能准确，特别是因为我们正在进入参数将被测量到百分比水平的精确宇宙学时代。
We present the analytical solutions for the evolution of matter density perturbations, for a model with a constant dark energy equation of state $w$ but when the effects of the dark energy perturbations are properly taken into account. We consider two cases, the first when the sound speed of the perturbations is zero $c_s^2=0$ and the general case $0 10 H_0$ or equivalently $k/h>0.0033 \textrm{Mpc}^{-1}$. We also estimate the corrections to the growth index $\gamma(z)$, commonly used to parametrize the growth-rate. We find that these corrections due to the DE perturbations affect the growth index $\gamma$ at the $3\%$ level. We also compare our new expressions for the growth index with other expressions already present in the literature and we find that the latter are less accurate than the ones we propose here. Therefore, our analytical calculations are necessary as the theoretical predictions for the fundamental parameters to be constrained by the upcoming surveys need to be as accurate as possible, especially since we are entering in the precise cosmology era where parameters will be measured to the percent level.