arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.06484astro-ph.CO
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广义相对论中的星系功率谱

Galaxy Power Spectrum in General Relativity

Nastassia Grimm, Fulvio Scaccabarozzi, Jaiyul Yoo, Sang Gyu Biern, Jinn-Ouk Gong

摘要:

本文给出了广义相对论中的星系功率谱。使用一种新的方法,我们得到的星系功率谱考虑到所有的相对论效应的观测。特别是,我们独立的调查几何,相对论效应不产生发散项(比例$k^{-4}P_m(k)$或$k^{-2}P_m(k)$在所有尺度),将模仿原始非高斯信号。这种对发散项的消除确实是等效原理所期望的,这意味着任何在实验尺度上作为均匀引力的扰动都无法测量。我们发现,在以前的计算中得到的非物理红外发散只发生由于没有考虑所有的广义相对论的贡献一致。尽管没有发散项,广义相对论效应代表的非发散项改变星系的功率谱在大尺度(小于视界尺度)。在我们的数值计算的完整的星系功率谱,我们显示了偏离标准的红移空间功率谱,由于这些非发散的修正。我们的结论是,相对论效应显着改变星系的功率谱在$k\lesssim k_{eq}$,他们需要考虑到在大尺度数据的分析。

英文摘要:

We present the galaxy power spectrum in general relativity. Using a novel approach, we derive the galaxy power spectrum taking into account all the relativistic effects in observations. In particular, we show independently of survey geometry that relativistic effects yield no divergent terms (proportional to $k^{-4}P_m(k)$ or $k^{-2}P_m(k)$ on all scales) that would mimic the signal of primordial non-Gaussianity. This cancellation of such divergent terms is indeed expected from the equivalence principle, meaning that any perturbation acting as a uniform gravity on the scale of the experiment cannot be measured. We find that the unphysical infrared divergence obtained in previous calculations occurred only due to not considering all general relativistic contributions consistently. Despite the absence of divergent terms, general relativistic effects represented by non-divergent terms alter the galaxy power spectrum at large scales (smaller than the horizon scale). In our numerical computation of the full galaxy power spectrum, we show the deviations from the standard redshift-space power spectrum due to these non-divergent corrections. We conclude that, as relativistic effects significantly alter the galaxy power spectrum at $k\lesssim k_{eq}$, they need to be taken into account in the analysis of large-scale data.

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