重子振荡的重建：拉格朗日理论的观点
Reconstructing Baryon Oscillations: A Lagrangian Theory Perspective
摘要：
最近，爱森斯坦和他的合作者提出了一种方法，从非线性演化的星系分布"重建"线性功率谱，以提高测量重子声学振荡的精度。我们在结构形成的拉格朗日图中重新表述了这种方法，以更好地理解这种方法的作用，以及由此产生的功率谱是什么。我们表明，重建不再现线性密度场，在二阶。然而，我们表明，它确实减少了阻尼的振荡，由于非线性结构的形成，解释了在模拟中看到的改进。我们的研究结果表明，重建的功率谱可能更好地建模为三个不同的功率谱的总和，每个功率谱在不同的波长范围内占主导地位，并具有不同的非线性阻尼项。最后，我们还表明，重建减少了功率谱中的模式耦合项，解释了为什么当考虑重建的功率谱时，减少了声学尺度的误校准。
英文摘要：
Recently Eisenstein and collaborators introduced a method to `reconstruct' the linear power spectrum from a non-linearly evolved galaxy distribution in order to improve precision in measurements of baryon acoustic oscillations. We reformulate this method within the Lagrangian picture of structure formation, to better understand what such a method does, and what the resulting power spectra are. We show that reconstruction does not reproduce the linear density field, at second order. We however show that it does reduce the damping of the oscillations due to non-linear structure formation, explaining the improvements seen in simulations. Our results suggest that the reconstructed power spectrum is potentially better modeled as the sum of three different power spectra, each dominating over different wavelength ranges and with different non-linear damping terms. Finally, we also show that reconstruction reduces the mode-coupling term in the power spectrum, explaining why mis-calibrations of the acoustic scale are reduced when one considers the reconstructed power spectrum.
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