Modelling baryon acoustic oscillations with perturbation theory and stochastic halo biasing
Modelling baryon acoustic oscillations with perturbation theory and stochastic halo biasing
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DOI：
10.1093/mnrasl/slt172
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发表时间：
2013-07
影响因子：
4.8
通讯作者：
F. Kitaura;G. Yepes;F. Prada
中科院分区：
文献类型：
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作者：
F. Kitaura;G. Yepes;F. Prada
在这项工作中，我们研究的基础上微扰理论和非线性随机偏置与新的PATCHY码的模拟晕目录的生成。特别是，我们使用增广拉格朗日微扰理论（ALPT）生成一个网格上的暗物质密度场从高斯波动，并计算奇特的速度场。ALPT基于大尺度上的二阶LPT（2LPT）和小尺度上的球形塌陷模型的组合。我们占的系统偏差的微扰方法从N体模拟与晕偏置采用指数偏置模型。然后，我们占随机偏置定义三个政权：低，中间和高密度政权，使用泊松分布在中间政权和负二项分布模型过度分散在高密度政权。由于我们在这项研究中的重点是大规模的晕，我们抑制在低密度制度的晕的产生。各种非线性和随机偏置参数以及密度阈值（五个）用大型BigMultiDark N体模拟进行校准，以匹配相应晕粒子数的功率谱。我们的模拟星表显示了在真实的空间和红移空间中的功率谱，对于具有典型BOSS CMASS星系数密度的晕样本，在z = 0.577时，在k ~ 1 h Mpc^-1范围内，功率谱与N体模拟结果在约2%的范围内是一致的。相应的相关函数是兼容的几个兆位差。我们还发现，忽略高密度区的过色散，在k ~ 0.4 h Mpc^-1处产生的功率谱偏差为10%。这些结果表明，需要考虑到一个准确的统计描述的星系集群精确的研究大规模的调查。
In this work we investigate the generation of mock halo catalogues based on perturbation theory and nonlinear stochastic biasing with the novel PATCHY-code. In particular, we use Augmented Lagrangian Perturbation Theory (ALPT) to generate a dark matter density field on a mesh starting from Gaussian fluctuations and to compute the peculiar velocity field. ALPT is based on a combination of second order LPT (2LPT) on large scales and the spherical collapse model on smaller scales. We account for the systematic deviation of perturbative approaches from N-body simulations together with halo biasing adopting an exponential bias model. We then account for stochastic biasing by defining three regimes: a low, an intermediate and a high density regime, using a Poisson distribution in the intermediate regime and the negative binomial distribution to model over-dispersion in the high density regime. Since we focus in this study on massive halos, we suppress the generation of halos in the low density regime. The various nonlinear and stochastic biasing parameters, and density thresholds (five) are calibrated with the large BigMultiDark N-body simulation to match the power spectrum of the corresponding halo population. Our mock catalogues show power spectra, both in real- and redshift-space, which are compatible with N-body simulations within about 2% up to k ~ 1 h Mpc^-1 at z = 0.577 for a sample of halos with the typical BOSS CMASS galaxy number density. The corresponding correlation functions are compatible down to a few Mpc. We also find that neglecting over-dispersion in high density regions produces power spectra with deviations of 10% at k ~ 0.4 h Mpc^-1. These results indicate the need to account for an accurate statistical description of the galaxy clustering for precise studies of large-scale surveys.