The impact of inhomogeneous subgrid clumping on cosmic reionization
The impact of inhomogeneous subgrid clumping on cosmic reionization
复制标题
不均匀亚网格聚集对宇宙再电离的影响
DOI：
10.1093/mnras/stz2986
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发表时间：
2020
影响因子：
4.8
通讯作者：
Mao Y
中科院分区：
文献类型：
--
作者：
Mao Y
宇宙再电离是由早期电离辐射源和汇之间的不平衡驱动的，两者都由小尺度结构主导，因此通常在宇宙学再电离模拟中通过亚网格模型处理。星系际氢的复合率通常由一个亚网格聚集因子来提高，该因子是1 n2/1 n2，它可以校正粗粒模拟网格间距以下的气体密度尺度中未解决的波动。我们详细地研究了这种不规则的次网格聚集对再电离及其观测的影响，如下：（1）以前的尝试通常低估了聚集因子，因为质量分辨率不够。我们进行了高resolutionN体模拟，解决了晕到预再电离牛仔裤质量，以获得时间依赖性，spatially varyinglocalclumping因子和拟合公式，其相关性与当地的超密度。(2)然后，我们进行了一个大规模的N-体和辐射传输模拟，占这种不均匀的次网格聚集通过应用这种聚集因子overdensity相关。增强复合显着减缓电离区域的扩展，延迟完成再电离和抑制21厘米功率谱在大尺度上的再电离的后期阶段。(3)我们还考虑了一个简化的处方，其中全球平均，时间演变成团因子从相同的高resolutionN体模拟均匀地应用于所有细胞的再电离模拟，而不是。用这个模型计算的观测值与非均匀聚集模型的观测值相当吻合，例如预测21厘米功率谱的误差在20%以内，这表明它可能是一个有用的近似值。
Cosmic reionization was driven by the imbalance between early sources and sinks of ionizing radiation, both of which were dominated by small-scale structure and are thus usually treated in cosmological reionization simulations by subgrid modelling. The recombination rate of intergalactic hydrogen is customarily boosted by a subgridclumping factor, 〈n2〉/〈n〉2, which corrects for unresolved fluctuations in gas densitynon scales below the grid-spacing of coarse-grained simulations. We investigate in detail the impact of thisinhomogeneoussubgrid clumping on reionization and its observables, as follows: (1) Previous attempts generally underestimated the clumping factor because of insufficient mass resolution. We perform a high-resolutionN-body simulation that resolves haloes down to the pre-reionization Jeans mass to derive the time-dependent, spatially varyinglocalclumping factor and a fitting formula for its correlation with local overdensity. (2) We then perform a large-scaleN-body and radiative transfer simulation that accounts for this inhomogeneous subgrid clumping by applying this clumping factor-overdensity correlation. Boosting recombination significantly slows the expansion of ionized regions, which delays completion of reionization and suppresses 21 cm power spectra on large scales in the later stages of reionization. (3) We also consider a simplified prescription in which the globally averaged, time-evolving clumping factor from the same high-resolutionN-body simulation is applied uniformly to all cells in the reionization simulation, instead. Observables computed with this model agree fairly well with those from the inhomogeneous clumping model, e.g. predicting 21 cm power spectra to within 20 per cent error, suggesting it may be a useful approximation.
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DOI：
10.1088/0004-637x/756/1/15
发表时间：
2011-09
期刊：
The Astrophysical Journal
影响因子：
--
作者：
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通讯作者：
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DOI：
10.1111/j.1365-2966.2006.10919.x
发表时间：
2006-03
影响因子：
4.8
作者：
G. Mellema;I. Iliev;U. Pen;P. R. S. Astron;S. Leiden;Cita;D. Astronomy;U. Austin
通讯作者：
G. Mellema;I. Iliev;U. Pen;P. R. S. Astron;S. Leiden;Cita;D. Astronomy;U. Austin
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DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
G. Worseck;J. Prochaska;J. O’Meara;George D. Becker;S. L. Ellison;S. López;A. Meiksin;B. M'enard;Michael T. Murphy;M. Fumagalli
通讯作者：
M. Fumagalli
DOI：
10.1088/2041-8205/756/1/l16
发表时间：
2012-06
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
K. Ahn;I. Iliev;P. Shapiro;G. Mellema;J. Koda;Y. Mao
通讯作者：
K. Ahn;I. Iliev;P. Shapiro;G. Mellema;J. Koda;Y. Mao
影响因子：
4.8
作者：
Anson D’Aloisio;Jun Zhang;P. Shapiro;Y. Mao
通讯作者：
Anson D’Aloisio;Jun Zhang;P. Shapiro;Y. Mao