The clustering of dark matter haloes: scale-dependent bias on quasi-linear scales
The clustering of dark matter haloes: scale-dependent bias on quasi-linear scales
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DOI：
10.1093/mnras/stw1702
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发表时间：
2015-09
影响因子：
4.8
通讯作者：
Charles Jose;C. Lacey;C. Baugh
中科院分区：
文献类型：
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作者：
Charles Jose;C. Lacey;C. Baugh
我们利用N体模拟研究了暗物质晕在红移0 − 5范围内的空间聚集，这些暗物质晕是由1 − 4σ涨落坍缩的。高红移晕（z ≥ 2）的晕偏置被发现是强非线性的，并且依赖于大于其维里半径（0.5 − 10 Mpc/h）的准线性标度。然而，在较低的红移处，非线性偏差的尺度依赖性较弱，并且在z 0处的准线性尺度上只有百分之几的量级。我们发现暗物质晕的标度依赖偏差的红移演化可以表示为四个物理参数的函数：晕的峰值高度，感兴趣标度下的非线性物质相关函数，均方根线性密度涨落的有效幂律指数和给定红移下的宇宙物质密度.这表明，晕偏置的尺度依赖性并不是暗物质功率谱的普适函数，这是通常假设的。我们提供了一个拟合函数的规模依赖晕偏置作为这四个参数的函数。我们的拟合再现了模拟结果，在红移范围0 ≤ z ≤ 5内的精度优于4%。我们还扩展了我们的模型表示的非线性偏差作为一个函数的线性物质相关函数。重要的是要将我们的结果纳入任何红移的暗物质晕的聚类模型，包括那些托管早期几代恒星和星系再电离之前。
We investigate the spatial clustering of dark matter halos, collapsing from 1 − 4σ fluctuations, in the redshift range 0 − 5 using N-body simulations. The halo bias of high redshift halos (z ≥ 2) is found to be strongly non-linear and scale-dependent on quasi-linear scales that are larger than their virial radii (0.5 − 10 Mpc/h). However, at lower redshifts, the scale-dependence of non-linear bias is weaker and and is of the order of a few percent on quasi-linear scales at z ∼ 0. We find that the redshift evolution of the scale dependent bias of dark matter halos can be expressed as a function of four physical parameters: the peak height of halos, the non-linear matter correlation function at the scale of interest, an effective power law index of the rms linear density fluctuations and the matter density of the universe at the given redshift. This suggests that the scale-dependence of halo bias is not a universal function of the dark matter power spectrum, which is commonly assumed. We provide a fitting function for the scale dependent halo bias as a function of these four parameters. Our fit reproduces the simulation results to an accuracy of better than 4% over the redshift range 0 ≤ z ≤ 5. We also extend our model by expressing the non-linear bias as a function of the linear matter correlation function. It is important to incorporate our results into the clustering models of dark matter halos at any redshift, including those hosting early generations of stars and galaxies before reionization.