Systematic bias in cosmic shear: extending the Fisher matrix
Systematic bias in cosmic shear: extending the Fisher matrix
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DOI：
10.1111/j.1365-2966.2008.13880.x
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发表时间：
2007-10
影响因子：
4.8
通讯作者：
A. Amara;A. Réfrégier
中科院分区：
文献类型：
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作者：
A. Amara;A. Réfrégier
我们描述了一种计算系统信号在参数估计中引入的偏差的方法，该方法使用Fisher矩阵形式的简单扩展。这允许我们计算最佳拟合参数相对于基准模型的偏移量，除了通常的统计误差椭圆。作为一种应用，我们研究了残差系统对层析弱透镜测量的影响。我们特别探讨了三种不同类型的形状测量系统：(i)无红移演化的加性系统；（ii）具有红移演化的加性系统；（三）乘数系统。在每种情况下，我们都考虑了系统信号的大范围尺度依赖和红移演化。对于未来类似dune的全天巡天，我们发现，对于轻微红移演化的情况，加性系统信号的方差应保持在10.7以下，以确保宇宙学参数的偏差次于统计误差。对于依赖于透镜信号的乘法系统，我们发现乘法标定m0需要控制在优于103的精度。我们发现，如果系统分类学假设的红移依赖过于简单，那么它们的影响可能会被低估。我们提供了简单的缩放关系，将这些要求扩展到任何测量几何形状，并讨论了我们的结果对当前和未来弱透镜测量的影响。
We describe a method for computing the biases that systematic signals introduce in parameter estimation using a simple extension of the Fisher matrix formalism. This allows us to calculate the offset of the best fit parameters relative to the fiducial model, in addition to the usual statistical error ellipse. As an application, we study the impact that residual systematics in tomographic weak lensing measurements. In particular we explore three different types of shape measurement systematics: (i) additive systematic with no redshift evolution; (ii) additive systematic with redshift evolution; and (iii) multiplicative systematic. In each case, we consider a wide range of scale dependence and redshift evolution of the systematics signal. For a future DUNE-like full sky survey, we find that, for cases with mild redshift evolution, the variance of the additive systematic signal should be kept below 10 7 to ensure biases on cosmological parameters that are sub-dominant to the statistical errors. For the multiplicative systematics, which depends on the lensing signal, we find the multiplicative calibration m0 needs to be controlled to an accuracy better than 10 3 . We find that the impact of systematics can be underestimated if their assumes redshift dependence is too simplistic. We provide simple scaling relations to extend these requirements to any survey geometry and discuss the impact of our results for current and future weak lensing surveys.