Inflation predicts that the Universe is spatially flat. The Planck 2018 measurements of the cosmic microwave background anisotropy favour a spatially closed universe at more than 2σ confidence level. We use model-independent methods to study the issue of cosmic curvature. The method reconstructs the Hubble parameter H(z) from cosmic chronometers data with the Gaussian process method. The distance modulus is then calculated with the reconstructed function H(z) and fitted by Type Ia supernovae data. Combining the cosmic chronometers and Type Ia supernovae data, we obtain Ωk0h2 = 0.102 ± 0.066 that is consistent with a spatially flat universe at the 2σ confidence level. By adding the redshift-space distortions data to the Type Ia supernovae data with a proposed novel model-independent method, we obtain $\Omega _{k0}h^2=0.117^{+0.058}_{-0.045}$ and no deviation from Λ cold dark matter (ΛCDM) model is found.

中文翻译：

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使用高斯过程法测量宇宙曲率

通货膨胀预测宇宙在空间上是平坦的。普朗克 2018 年对宇宙微波背景各向异性的测量有利于空间闭合宇宙的置信度超过 2σ。我们使用与模型无关的方法来研究宇宙曲率问题。该方法利用高斯过程方法从宇宙计时器数据中重建哈勃参数 H(z)。然后用重建函数 H(z) 计算距离模量，并用 Ia 型超新星数据拟合。结合宇宙天文台和 Ia 型超新星数据，我们得到 Ωk0h2 = 0.102 ± 0.066，这与 2σ 置信水平的空间平坦宇宙一致。通过提出的新的模型无关方法将红移空间畸变数据添加到 Ia 型超新星数据中，我们获得了 $\Omega _{k0}h^2=0.117^{+0.058}_{-0。