The BAHAMAS project: evaluating the accuracy of the halo model in predicting the non-linear matter power spectrum
The BAHAMAS project: evaluating the accuracy of the halo model in predicting the non-linear matter power spectrum
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DOI：
10.1093/mnras/stab2834
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发表时间：
2021-10-20
影响因子：
4.8
通讯作者：
Font, Andreea S.
中科院分区：
文献类型：
--
作者：
Acuto, Alberto;McCarthy, Ian G.;Font, Andreea S.
晕模型在宇宙学研究中被广泛用于预测宇宙中大尺度结构的生长。然而，到目前为止，相对较少的直接比较晕模型与更精确（但计算成本更高）的宇宙学模拟。我们测试了晕模型在再现非线性物质功率谱P（k）方面的准确性，当晕模型的主要输入（特别是物质密度分布、晕质量函数和线性偏差）直接取自BAHAMAS模拟时，我们评估了晕模型从相同模拟再现P（k）的效果。我们表明，晕轮模型一般复制P（k）在深非线性制度（1-晕），通常百分之几的准确性，但努力复制（约。误差15%）P（k）在0.1的中间尺度小于或接近于k [h/Mpc]在z = 0时小于或接近于3，标志着1-halo和2-halo项之间的过渡。我们表明，这种错误的大小是一个强大的功能的晕质量定义（通过其影响晕的径向范围）和红移。此外，我们还检验了晕模型在恢复重子对P（k）的相对影响方面的准确性。我们表明，在恢复绝对P（k）的系统误差在很大程度上取消考虑重子的相对影响。这表明，晕模型可以对重子抑制做出精确的预测，为调整重子和相关过程存在的无碰撞物质功率谱提供了一种快速准确的方法。
The halo model formalism is widely adopted in cosmological studies for predicting the growth of large-scale structure in the Universe. However, to date there have been relatively few direct comparisons of the halo model with more accurate (but much more computationally expensive) cosmological simulations. We test the accuracy of the halo model in reproducing the non-linear matter power spectrum, P(k), when the main inputs of the halo model (specifically the matter density profiles, halo mass function, and linear bias) are taken directly from the BAHAMAS simulations, and we assess how well the halo model reproduces P(k) from the same simulations. We show that the halo model generally reproduces P(k) in the deep non-linear regime (1-halo) to typically a few per cent accuracy, but struggles to reproduce (approx. 15 per cent error) P(k) at intermediate scales of 0.1 less than or similar to k [h/Mpc] less than or similar to 3 at z = 0, marking the transition between the 1-halo and 2-halo terms. We show that the magnitude of this error is a strong function of the halo mass definition (through its effects on radial extent of haloes) and of redshift. Furthermore, we test the accuracy of the halo model in recovering the relative impact of baryons on P(k). We show that the systematic errors in recovering the absolute P(k) largely cancel when considering the relative impact of baryons. This suggests that the halo model can make precise predictions for the baryonic suppression, offering a fast and accurate way to adjust collisionless matter power spectra for the presence of baryons and associated processes.