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arXiv 1803.02477astro-ph.CO
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强度映射互相关II:包括散粒噪声的HI晕轮模型

Intensity mapping cross-correlations II: HI halo models including shot noise

L. Wolz, S. G. Murray, C. Blake, J. S. Wyithe

摘要:

HI强度映射数据使用中性氢气(HI)的积分发射追踪大尺度结构物质分布。的互相关的强度地图与光学星系调查可以减轻前景和系统的影响,但已被证明显着依赖于星系演化参数的HI和光学样本。先前,我们已经表明,互相关的散粒噪声与光学样本的HI含量成比例,使得散粒噪声估计推断这些样本的平均HI质量。在这篇文章中,我们提出了一个自适应框架,用于HI强度图与星系样本的互相关,使用我们的晕模型形式主义的实现(Murray et al 2018,在准备中),该框架利用星系的晕占据分布来预测它们的功率谱。我们比较了两个HI人口模型,分别跟踪空间晕和星系分布,并提出了他们的自动和交叉功率谱与相关的星系样本。我们发现,HI模型的选择和星系样本内的HI分布的自相关和互相关的形状有轻微的意义,但高度影响测量的散粒噪声幅度的估计,一个发现,我们证实与模拟。我们演示了HI晕占领模型的参数估计,并主张这个框架的解释未来的实验数据,通过互相关散粒噪声确定光学星系样本的HI质量的前景。

英文摘要:

HI intensity mapping data traces the large-scale structure matter distribution using the integrated emission of neutral hydrogen gas (HI). The cross-correlation of the intensity maps with optical galaxy surveys can mitigate foreground and systematic effects, but has been shown to significantly depend on galaxy evolution parameters of the HI and the optical sample. Previously, we have shown that the shot noise of the cross-correlation scales with the HI content of the optical samples, such that the shot noise estimation infers the average HI masses of these samples. In this article, we present an adaptive framework for the cross-correlation of HI intensity maps with galaxy samples using our implementation of the halo model formalism (Murray et al 2018, in prep) which utilises the halo occupation distribution of galaxies to predict their power spectra. We compare two HI population models, tracing the spatial halo and the galaxy distribution respectively, and present their auto- and cross-power spectra with an associated galaxy sample. We find that the choice of the HI model and the distribution of the HI within the galaxy sample have minor significance for the shape of the auto- and cross-correlations, but highly impact the measured shot noise amplitude of the estimators, a finding we confirm with simulations. We demonstrate parameter estimation of the HI halo occupation models and advocate this framework for the interpretation of future experimental data, with the prospect of determining the HI masses of optical galaxy samples via the cross-correlation shot noise.

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