Systematic effects in the sound horizon scale measurements
Systematic effects in the sound horizon scale measurements
复制标题
声层尺度测量中的系统效应
DOI：
10.1111/j.1365-2966.2006.11385.x
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发表时间：
2006
影响因子：
4.8
通讯作者：
R. Smith
中科院分区：
文献类型：
--
作者：
J. Guzik;G. Bernstein;R. Smith
我们调查了三个潜在的来源，假设一个非常简单的重子声振荡（BAO）尺度的估计提供了一个标准的统治者的距离估计的偏见。这些是结构的非线性演变、尺度依赖性偏差和调查窗口函数估计中的误差的影响。所使用的简单估计量是平滑相关函数的峰值，如果对密度场应用适当的低通滤波，则该平滑相关函数提供接近最优的BAO尺度的方差。虽然最大似然估计可以消除偏差，如果系统误差的形式是完全建模，我们估计未建模或错误建模的系统误差的潜在影响。使用Smith等人的处方的非线性结构增长在相关函数估计器下在z ≥ 1时使声学标度偏差<0.3%。在晕模型计算所建议的领域中，由于尺度依赖星系偏差的代表性但过于简单的模型导致的偏差在z ≥ 1时低于1%，预计这将低于1000-deg 2光谱调查的统计误差。由于调查窗口函数误差的距离偏差是在一个简单的封闭的形式，它示出，它必须保持在2%以下，以便不偏置声学标度超过1%，在z = 1，虽然实际的公差可以更大，取决于星系的偏见。如果不进行修正，这些偏差与雄心勃勃的调查的统计错误相当。我们表明，均方根光度零点误差（在极限星等25等）低于0.14和0.01等红移z = 1（红星系）和z = 3（莱曼break星系），分别需要，以保持距离估计偏差低于百分之一。
We investigate three potential sources of bias in distance estimations made assuming that a very simple estimator of the baryon acoustic oscillation (BAO) scale provides a standard ruler. These are the effects of the non-linear evolution of structure, scale-dependent bias and errors in the survey window function estimation. The simple estimator used is the peak of the smoothed correlation function, which provides a variance in the BAO scale that is close to optimal, if appropriate low-pass filtering is applied to the density field. While maximum-likelihood estimators can eliminate biases if the form of the systematic error is fully modelled, we estimate the potential effects of unmodelled or mis-modelled systematic errors. Non-linear structure growth using the Smith et al. prescription biases the acoustic scale by <0.3 per cent at z ≥ 1 under the correlation-function estimator. The biases due to representative but simplistic models of scale-dependent galaxy bias are below 1 per cent at z ≥ 1 for bias behaviour in the realms suggested by halo model calculations, which is expected to be below the statistical errors for a 1000-deg 2 spectroscopic survey. The distance bias due to a survey window function error is given in a simple closed form and it is shown that it has to be kept below 2 per cent so as not to bias acoustic scale more than 1 per cent at z = 1, although the actual tolerance can be larger depending upon galaxy bias. These biases are comparable to statistical errors for ambitious surveys if no correction is made for them. We show that rms photometric zero-point errors (at limiting magnitude 25 mag) below 0.14 and 0.01 mag for redshift z = 1 (red galaxies) and z = 3 (Lyman-break galaxies), respectively, are required in order to keep the distance estimator bias below 1 per cent.