Measuring the scale dependence of intrinsic alignments using multiple shear estimates
Measuring the scale dependence of intrinsic alignments using multiple shear estimates
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DOI：
10.1093/mnras/sty1444
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发表时间：
2018-02
影响因子：
4.8
通讯作者：
C. D. Leonard;R. Mandelbaum
中科院分区：
文献类型：
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作者：
C. D. Leonard;R. Mandelbaum
我们提出了一种新的方法来测量本征排列(IA)污染对星系透镜信号的尺度依赖性，该方法利用了适用于同一源星系样本的多个剪切估计方法。通过利用形状噪声和宇宙方差的相关性，与依赖于来自多个光度红移箱的透镜信号的差异的方法相比，我们的方法可以提供测量的IA信号的信噪比增加。对于使用LSST源和DESI透镜的星系-星系透镜测量，我们的方法对IA信号的信噪比预计比Blazek等人的方法提高了2倍。2012年，对于产生显著不同的测量IA幅度和高度相关的形状噪声项的剪切估计对。我们表明，在使用我们的方法测量内在比对时，统计误差必然是主要的。我们还考虑了Blazek等人在身体上的扩展。2012年的一种方法，它假设所有附近的星系对，而不仅仅是多余的星系对，都受到IA的影响。在这种情况下，Blazek等人的方法的信噪比。2012年的情况有所改善。
We present a new method for measuring the scale dependence of the intrinsic alignment (IA) contamination to the galaxy-galaxy lensing signal, which takes advantage of multiple shear estimation methods applied to the same source galaxy sample. By exploiting the resulting correlation of both shape noise and cosmic variance, our method can provide an increase in the signal-to-noise of the measured IA signal as compared to methods which rely on the difference of the lensing signal from multiple photometric redshift bins. For a galaxy-galaxy lensing measurement which uses LSST sources and DESI lenses, the signal-to-noise on the IA signal from our method is predicted to improve by a factor of $\sim 2$ relative to the method of Blazek et al. 2012, for pairs of shear estimates which yield substantially different measured IA amplitudes and highly correlated shape noise terms. We show that statistical error necessarily dominates the measurement of intrinsic alignments using our method. We also consider a physically motivated extension of the Blazek et al. 2012 method which assumes that all nearby galaxy pairs, rather than only excess pairs, are subject to IA. In this case, the signal-to-noise of the method of Blazek et al. 2012 is improved.