标题： 关于结构增长的鲁棒分析 显示英文标题

标题： On a robust analysis of the growth of structure

摘要： 当前宇宙学的矛盾表明，在不同的宇宙时期测试标准 $\Lambda$CDM 模型的预测至关重要。 宇宙结构形成的非常有吸引力的检验是我们的宇宙中结构的增长率 $f$，通常通过增长指数 $\gamma$参数化，在标准 $\Lambda$CDM 情况下为 $f\equiv \Omega_m(a)^\gamma$和 $\gamma \simeq 0.55$。 最近的研究声称，从各种宇宙学观测中出现了结构增长的抑制，其特征是 $\gamma>0.55$。 通过采用不同的自洽增长参数化方案，我们在这里显示，$\gamma<0.55$，而是得到\emph{结构今日的增强增长}。这种偏好通过宇宙微波背景观测、超新星 Ia 和重子声学振荡测量达到$3\sigma$显著性。添加宇宙微波背景引力透镜数据将这种偏好放松到$2\,\sigma$水平，因为更大的透镜效应总是可以通过更小的结构增长来补偿，或者等价地，通过$\gamma>0.55$。我们还将透镜幅度$A_{\rm L}$作为自由参数包含在我们的数据分析中，显示对于$A_{\rm L}>1$的偏好仍然存在，除非在某些特定参数化情况下包含透镜观测。 我们也未发现对$A_{\rm L}$的多极依赖性的显著偏好。 为了进一步重新评估非标准增长的影响，我们通过N体模拟计算了不同$\gamma$值下的暗物质密度场、暗物质晕质量函数和晕密度剖面。 未来来自平方公里阵列的观测将使当前对$\gamma$参数的误差减少三倍，这最终可能解决这个问题。 显示英文摘要

摘要： Current cosmological tensions show that it is crucial to test the predictions from the canonical $\Lambda$CDM paradigm at different cosmic times. One very appealing test of structure formation in the universe is the growth rate of structure in our universe $f$, usually parameterized via the growth index $\gamma$, with $f\equiv \Omega_m(a)^\gamma$ and $\gamma \simeq 0.55$ in the standard $\Lambda$CDM case. Recent studies have claimed a suppression of the growth of structure from a variety of cosmological observations, characterized by $\gamma>0.55$. By employing different self-consistent growth parameterizations schemes, we show here that $\gamma<0.55$, obtaining instead \emph{an enhanced growth of structure today}. This preference reaches the $3\sigma$ significance using Cosmic Microwave Background observations, Supernova Ia and Baryon Acoustic Oscillation measurements. The addition of Cosmic Microwave Background lensing data relaxes such a preference to the $2\,\sigma$ level, since a larger lensing effect can always be compensated with a smaller structure growth, or, equivalently, with $\gamma>0.55$. We have also included the lensing amplitude $A_{\rm L}$ as a free parameter in our data analysis, showing that the preference for $A_{\rm L}>1$ still remains, except for some particular parameterizations when lensing observations are included. We also not find any significant preference for a multipole dependence of $A_{\rm L}$. To further reassess the effects of a non-standard growth, we have computed by means of N-body simulations the dark matter density fields, the dark matter halo mass functions and the halo density profiles for different values of $\gamma$. Future observations from the Square Kilometer Array, reducing by a factor of three the current errors on the $\gamma$ parameter, could finally settle the issue.