用MICE模拟宇宙：大质量星系团的丰度
Simulating the Universe with MICE: The abundance of massive clusters
摘要：
我们介绍了一套新的大型N体运行，MICE模拟，提供了一个独特的组合非常大的宇宙体积与良好的质量分辨率。它们遵循的是约85亿个粒子（2048^3）的引力演化过程，其体积可达450（Gpc/h）^3。我们的主要目标是精确地建模和校准即将到来的天文调查将使用的基本宇宙学探测器。在这里，我们利用非常大的体积的MICE作出一个强大的采样晕质量函数（MF）的高质量尾部。我们讨论和避免可能的系统效应在我们的研究，并做了详细的分析，不同的误差估计。我们发现，可用的晕局部丰度拟合（Warren et al.（2006））与MICE中高达M ~ 10^{14} \Msun的丰度匹配良好，但对于更大的质量存在显著偏差，在M = 3.16 x 10^{14} \Msun（10^{15} \Msun）时，将质量函数低估了10%（30%）。类似地，广泛使用的Sheth & Tormen（1999）拟合，如果外推到假设普适性的高红移，则对于M ~ [7 - 2.5 - 0.8] x 10^{14} \Msun（$ν= δ_c/σ~ 3$），在z=0，0.5，1处的星系团丰度分别被低估了30%，20%和15%。我们提供了一个在质量上超过5个数量级有效的晕MF的重新校准，10^{10} < M/（\Msun）< 10^{15}，准确地描述了它的红移演化到z=1。我们探讨了这种重新校准对暗能量测定的影响，并得出结论，对于中等深度（z <= 1）的调查，使用可用的拟合可能会系统地使w的估计值偏差高达50%。MICE光环目录可在http://www.ice.cat/mice上公开获取
英文摘要：
We introduce a new set of large N-body runs, the MICE simulations, that provide a unique combination of very large cosmological volumes with good mass resolution. They follow the gravitational evolution of ~ 8.5 billion particles (2048^3) in volumes covering up to 450 (Gpc/h)^3. Our main goal is to accurately model and calibrate basic cosmological probes that will be used by upcoming astronomical surveys. Here we take advantage of the very large volumes of MICE to make a robust sampling of the high-mass tail of the halo mass function (MF). We discuss and avoid possible systematic effects in our study, and do a detailed analysis of different error estimators. We find that available fits to the local abundance of halos (Warren et al. (2006)) match well the abundance in MICE up to M ~ 10^{14}\Msun, but significantly deviate for larger masses, underestimating the mass function by 10% (30%) at M = 3.16 x 10^{14}\Msun (10^{15}\Msun). Similarly, the widely used Sheth & Tormen (1999) fit, if extrapolated to high redshift assuming universality, leads to an underestimation of the cluster abundance by 30%, 20% and 15% at z=0, 0.5, 1 for M ~ [7 - 2.5 - 0.8] x 10^{14}\Msun respectively ($ν= δ_c/σ~ 3$). We provide a re-calibration of the halo MF valid over 5 orders of magnitude in mass, 10^{10} < M/(\Msun) < 10^{15}, that accurately describes its redshift evolution up to z=1. We explore the impact of this re-calibration on the determination of dark-energy, and conclude that using available fits may systematically bias the estimate of w by as much as 50% for medium-depth (z <= 1) surveys. MICE halo catalogues are publicly available at http://www.ice.cat/mice
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