Reconstructing H i power spectrum with minimal parameters using the dark matter distribution beyond haloes
Reconstructing H i power spectrum with minimal parameters using the dark matter distribution beyond haloes
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DOI：
10.1093/mnras/stab2284
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发表时间：
2020-11
影响因子：
4.8
通讯作者：
R. Ando;A. Nishizawa;I. Shimizu;K. Nagamine
中科院分区：
文献类型：
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作者：
R. Ando;A. Nishizawa;I. Shimizu;K. Nagamine
多个射电望远镜实验对21厘米线的强度测绘将探测后再电离时代宇宙的大尺度结构。这需要中性氢（H i）聚类的理论框架，如重子声学振荡（BAO）分析的H i功率谱建模。我们提出了一种利用n体模拟从暗物质分布重建H - i图的新方法。一些研究试图通过在暗物质晕中心粘贴H气体，假设晕和H质量之间的关系，用n体模拟来计算H功率谱。另一方面，本文提出的方法再现了从晕中心截取特定尺度的模拟暗物质分布的H功率谱。该方法在BAO尺度（k < 1 H /Mpc）下能较好地再现H - i功率谱的斜率。此外，我们发现自旋温度的波动在功率谱中最多改变了8%的亮度温度功率谱，而这在再电离后时期往往被忽略。最后，我们通过比较暗物质晕周围的黑洞和暗物质的密度分布来讨论我们的方法是如何工作的。
Intensity mapping of 21-cm line by several radio telescope experiments will probe the large-scale structure of the Universe in the post-reionization epoch. It requires a theoretical framework of neutral hydrogen (H i) clustering, such as modelling of H i power spectrum for baryon acoustic oscillations (BAO) analysis. We propose a new method for reconstructing the H i map from dark matter distribution using N-body simulations. Several studies attempt to compute the H i power spectrum with N-body simulations by pasting H i gas at the dark matter halo centre, assuming the relation between the halo and H i masses. On the other hand, the method proposed in this paper reproduces the H i power spectrum from simulated dark matter distribution truncated at specific scales from the halo centre. With this method, the slope of H i power spectrum is reproduced well at the BAO scales, k < 1 h/Mpc. Furthermore, we find the fluctuation of spin temperature, which is often ignored at the post-reionization epoch, alters the power spectrum of brightness temperature by at most 8 per cent in the power spectrum. Finally, we discuss how our method works by comparing the density profiles of H i and dark matter around the dark matter haloes.