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arXiv 1702.03004astro-ph.CO
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互相关的2D和3D星系巡天

Cross-correlating 2D and 3D galaxy surveys

Samuel Passaglia, Alessandro Manzotti, Scott Dodelson

摘要:

星系巡天探测结构形成和膨胀率,使它们成为了解暗宇宙的有希望的途径。测光巡天精确地绘制了给定红移范围内星系位置和形状的2D分布图,而光谱巡天提供了星系分布的稀疏3D图。我们提出了一种方法来分析重叠的2D和3D地图联合,而不会丢失信息。我们表示3D地图使用球面傅里叶-贝塞尔(sFB)模式,保留径向覆盖,同时占球形天空的几何形状,我们分解的球谐基础上的2D地图。在这些基地,一个简单的表达式存在的两个领域的互相关。一个非常强大的应用是能够同时约束测光样本的红移分布,样本偏差和宇宙学参数。我们使用我们的框架表明,DESI和LSST的组合分析,可以改善宇宙学的限制因素的${\sim}1.2$到${\sim}1.8$的区域,它们重叠相对于相同大小的不相交的区域。我们还表明,在DES和SDSS-III的条纹82的重叠,互相关改善了$z$参数的约束,${\sim}2$的因素,以${\sim}12$内部的照片- $z$重建。

英文摘要:

Galaxy surveys probe both structure formation and the expansion rate, making them promising avenues for understanding the dark universe. Photometric surveys accurately map the 2D distribution of galaxy positions and shapes in a given redshift range, while spectroscopic surveys provide sparser 3D maps of the galaxy distribution. We present a way to analyse overlapping 2D and 3D maps jointly and without loss of information. We represent 3D maps using spherical Fourier-Bessel (sFB) modes, which preserve radial coverage while accounting for the spherical sky geometry, and we decompose 2D maps in a spherical harmonic basis. In these bases, a simple expression exists for the cross-correlation of the two fields. One very powerful application is the ability to simultaneously constrain the redshift distribution of the photometric sample, the sample biases, and cosmological parameters. We use our framework to show that combined analysis of DESI and LSST can improve cosmological constraints by factors of ${\sim}1.2$ to ${\sim}1.8$ on the region where they overlap relative to identically sized disjoint regions. We also show that in the overlap of DES and SDSS-III in Stripe 82, cross-correlating improves photo-$z$ parameter constraints by factors of ${\sim}2$ to ${\sim}12$ over internal photo-$z$ reconstructions.

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