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arXiv 0903.4288astro-ph.CO
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偏差演变对综合Sachs-Wolfe效应测量的影响:参数估计中的误差和偏差

Implications of bias evolution on measurements of the integrated Sachs-Wolfe effect: errors and biases in parameter estimation

Bjoern Malte Schaefer, Marian Douspis, Nabila Aghanim

摘要:

本文的主题是量化的偏差和偏差演变的不确定性的综合萨克斯-沃尔夫效应的测量的解释,特别是宇宙学参数的估计的影响。本文结合普朗克微波巡天和EUCLID主星系样本,用Fisher矩阵分析了暗能量宇宙学参数与偏差演化之间的简并关系,其中偏差演化b(a)=b_0+(1-a)b_a由b_0和b_a两个参数模拟。由于改变了距离加权函数,使用现实的偏置模型在大角度尺度上引入了iSW频谱的特征抑制。在扩展的Fisher形式主义中,量化了在具有恒定偏差的宇宙学框架中解释具有演化偏差的数据时估计宇宙学参数的误差。我们发现,所有参数的最佳拟合值的移动量相媲美的统计精度:估计偏差的统计精度的单位为1.19为欧米茄_m,0.27为sigma_8,和0.72为w的偏差演变与b_a=1。将b_a作为自由参数保持开放会降低统计精度,特别是在Omega_m和w上。

英文摘要:

The subject of this paper is a quantification of the impact of uncertainties in bias and bias evolution on the interpretation of measurements of the integrated Sachs-Wolfe effect, in particular on the estimation of cosmological parameters. We carry out a Fisher-matrix analysis for quantifying the degeneracies between the parameters of a dark energy cosmology and bias evolution, for the combination of the PLANCK microwave sky survey with the EUCLID main galaxy sample, where bias evolution b(a)=b_0+(1-a)b_a is modelled with two parameters b_0 and b_a. Using a realistic bias model introduces a characteristic suppression of the iSW-spectrum on large angular scales, due to the altered distance-weighting functions. The errors in estimating cosmological parameters if the data with evolving bias is interpreted in the framework of cosmologies with constant bias is quantified in an extended Fisher-formalism. We find that the best-fit values of all parameters are shifted by an amount comparable to the statistical accuracy: The estimation bias in units of the statistical accuracy amounts to 1.19 for Omega_m, 0.27 for sigma_8, and 0.72 for w for bias evolution with b_a=1. Leaving b_a open as a free parameter deteriorates the statistical accuracy, in particular on Omega_m and w.

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