Calibrating the baryon oscillation ruler for matter and halos
Calibrating the baryon oscillation ruler for matter and halos
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DOI：
10.1103/physrevd.80.063508
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发表时间：
2009-06
影响因子：
5
通讯作者：
N. Padmanabhan;M. White
中科院分区：
文献类型：
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作者：
N. Padmanabhan;M. White
我们结合微扰理论和N体模拟来描述暗物质和晕追踪的重子声学特征的非线性演化。我们证实，由暗物质跟踪的声学峰是扩大和移位的结构形式，这种转变是很好地描述了二阶微扰理论。这些位移持续暗物质晕，是一个简单的函数晕偏差，与位移（大部分）增加的偏见。扩展我们的微扰理论的结果，晕简单的两个参数的偏差模型（无论是在拉格朗日和欧拉空间）定量地解释了所观察到的变化。特别是，我们证明，有额外的条款，有助于转移，是缺席的事情。在z = 0时，物质的位移约为0.5%，B = 1的晕使声学标度移动约0.2%，而B = 2的晕使声学标度移动约0.5%;这些位移在更高的红移时减少了增长因子D（z）的平方。这些结果很容易推广到星系内的晕模型，在那里我们表明，简单的星系模型表现出略大于相应的偏差晕，由于卫星在高质量晕的贡献的变化。虽然我们的重点是在真实的空间，我们的结果作出具体的预测红移空间。对于目前流行的宇宙学模型，我们发现在z = 0时，晕的位移增加了~0.3%;在高z时，它们增加了~0.5%D 2。我们的研究结果表明，这些理论系统小于即将到来的调查的统计精度，即使忽略这里讨论的校正。简单的建模，沿着这里讨论的路线，有可能减少这些系统到宇宙方差有限调查的水平以下。
We characterize the nonlinear evolution of the baryon acoustic feature as traced by the dark matter and halos, using a combination of perturbation theory and N-body simulations. We confirm that the acoustic peak traced by the dark matter is both broadened and shifted as structure forms, and that this shift is well described by second-order perturbation theory. These shifts persist for dark matter halos, and are a simple function of halo bias, with the shift (mostly) increasing with increasing bias. Extending our perturbation theory results to halos with simple two parameter bias models (both in Lagrangian and Eulerian space) quantitatively explains the observed shifts. In particular, we demonstrate that there are additional terms that contribute to the shift that are absent for the matter. At z = 0 for currently favored cosmologies, the matter shows shifts of ~0.5%, b = 1 halos shift the acoustic scale by ~0.2%, while b = 2 halos shift it by ~0.5%; these shifts decrease by the square of the growth factor D(z) at higher redshifts. These results are easily generalized to galaxies within the halo model, where we show that simple galaxy models show marginally larger shifts than the correspondingly biased halos, due to the contribution of satellites in high mass halos. While our focus here is on real space, our results make specific predictions for redshift space. For currently favored cosmological models, we find that the shifts for halos at z = 0 increase by ~0.3%; at high z, they increase by ~0.5%D 2 . Our results demonstrate that these theoretical systematics are smaller than the statistical precision of upcoming surveys, even if one ignored the corrections discussed here. Simple modeling, along the lines discussed here, has the potential to reduce these systematics to below the levels of cosmic variance limited surveys.