Title: Probing Cosmology beyond $Λ$CDM using the SKA Show Chinese title

Title: 利用SKA探测$Λ$CDM以外的宇宙学

Abstract: The cosmological principle states that the Universe is statistically homogeneous and isotropic at large distance scales. There currently exist many observations which indicate a departure from this principle. It has been shown that many of these observations can be explained by invoking superhorizon cosmological perturbations and may be consistent with the Big Bang paradigm. Remarkably, these modes simultaneously explain the observed Hubble tension, i.e., the discrepancy between the direct and indirect measurements of the Hubble parameter. We propose several tests of the cosmological principle using SKA. In particular, we can reliably extract the signal of dipole anisotropy in the distribution of radio galaxies. The superhorizon perturbations also predict a significant redshift dependence of the dipole signal which can be nicely tested by the study of signals of reionization and the dark ages using SKA. We also propose to study the alignment of radio galaxy axes as well as their integrated polarization vectors over distance scales ranging from a few Mpc to Gpc. We discuss data analysis techniques that can reliably extract these signals from data. Show Chinese abstract

Abstract: 宇宙学原理指出，在大距离尺度上，宇宙在统计上是均匀和各向同性的。 目前存在许多观测结果表明偏离了这一原理。 已经证明，这些观测中的许多可以通过引入超视界宇宙学扰动来解释，并可能与大爆炸范式一致。 值得注意的是，这些模式同时解释了观测到的哈勃张力，即直接和间接测量哈勃参数之间的差异。 我们提出使用SKA对宇宙学原理进行若干测试。 特别是，我们可以可靠地提取射电星系分布中二极各向异性的信号。 超视界扰动还预测了二极信号的显著红移依赖性，这可以通过利用SKA研究再电离和黑暗时代信号来进行良好测试。 我们还建议研究射电星系轴的对齐情况以及它们的积分偏振矢量，在从几兆秒差距到吉秒差距的距离尺度上进行研究。 我们讨论了可以从数据中可靠提取这些信号的数据分析技术。