Lagrangian displacement field estimators in cosmology
Lagrangian displacement field estimators in cosmology
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DOI：
10.1103/physrevd.107.123523
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发表时间：
2022-11
影响因子：
5
通讯作者：
A. Ota;H. Seo;S. Saito;F. Beutler
中科院分区：
文献类型：
--
作者：
A. Ota;H. Seo;S. Saito;F. Beutler
后期的非线性拉格朗日位移场与初始场高度相关，因此重建它可以使我们提取原始宇宙学信息。我们以前的工作[1]使用文献[1]提出的迭代方法，仔细地研究了由晚期时间密度场重建的位移场。[2]并且发现它不完全收敛到真实的基础位移场(例如，在$k\sim 0.2\ihMpc$在$z=0.6$处的$\sim 8\$偏移量)。我们还建立了重建场的拉格朗日微扰理论模型，但该模型不能解释以前工作中真实场和重建场之间的差异。由于样本的离散性，误差的主要来源被推测为位移估计器中的数值伪影。本文提出了两种新的位移场估计方法，即归一化动量估计~(NME)和重标恢复估计~(RRE)，以减少这种数值离散性的影响。我们证明了差异参考文献。[1]报道不是由于数字伪影。我们的结论是，文献[1]中的方法是正确的。[2]不能完全重建我们所研究的红移处的非线性位移场的形状，但它仍然是一种有效的BaO重建方法。同时，通过有效场论方法对重建过程中的紫外光敏感项进行了适当的解释，我们将重建位移场的理论模型改进了近5倍，从原来的$sim 15，提高到了红移$z=0.6的几个ksim 0.2，ihMpc的水平。
The late-time nonlinear Lagrangian displacement field is highly correlated with the initial field, so reconstructing it could enable us to extract primordial cosmological information. Our previous work [1] carefully studied the displacement field reconstructed from the late time density field using the iterative method proposed by Ref. [2] and found that it does not fully converge to the true, underlying displacement field (e.g., $\sim 8\%$ offset at $k\sim 0.2 \ihMpc$ at $z=0.6$). We also constructed the Lagrangian perturbation theory model for the reconstructed field, but the model could not explain the discrepancy between the true and the reconstructed fields in the previous work. The main sources of the discrepancy were speculated to be a numerical artifact in the displacement estimator due to the discreteness of the sample. In this paper, we develop two new estimators of the displacement fields to reduce such numerical discreteness effect, the normalized momentum estimator~(NME) and the rescaled resumed estimator~(RRE). We show that the discrepancy Ref. [1] reported is not due to the numerical artifacts. We conclude that the method from Ref. [2] cannot fully reconstruct the shape of the nonlinear displacement field at the redshift we studied, while it is still an efficient BAO reconstruction method. In parallel, by properly accounting for the UV-sensitive term in a reconstruction procedure with an effective field theory approach, we improve the theoretical model for the reconstructed displacement field, by almost five times, from $\sim 15\%$ to the level of a few \% at $k\sim 0.2\ihMpc$ at the redshift $z=0.6$.