论文标题
弱透镜数据中星系形状和大小的固有和外在相关性
Intrinsic and extrinsic correlations of galaxy shapes and sizes in weak lensing data
论文作者
论文摘要
本文的主题是建立一个物理模型，描述由于弱重力镜头而引起的星系的形状和大小相关性，以及椭圆星系与宇宙大规模结构产生的引力场的直接潮汐相互作用。为椭圆星系设置线性固有对齐模型，该模型参数为星系对外部潮汐剪切场的反应由速度分散控制，我们预测形状和尺寸的弱透镜的固有相关性和互相相关性，并将两种类型的光谱与固定型相融合。我们量化了固有形状和大小相关性的可观察性，并与Fisher形式的正态主义估计，从欧几里得弱透镜调查确定对齐参数的能力如何。具体而言，我们发现弱透镜收敛光谱的污染物具有内在尺寸的相关性，在宽的多产范围内，高达10％$ \ ell = 100 \ ldots300 $，相应的交叉相关表现出符号变化，类似于弱透镜剪切剪切剪切剪切和固有的形状之间的交叉相关。对齐参数的确定得出的精度为欧几里得的几个百分比，我们表明所有形状和许多大小相关性都应与欧几里得一起测量。
The subject of this paper is to build a physical model describing shape and size correlations of galaxies due to weak gravitational lensing and due to direct tidal interaction of elliptical galaxies with gravitational fields sourced by the cosmic large-scale structure. Setting up a linear intrinsic alignment model for elliptical galaxies which parameterises the reaction of the galaxy to an external tidal shear field is controlled by the velocity dispersion, we predict intrinsic correlations and cross-correlations with weak lensing for both shapes and sizes, juxtaposing both types of spectra with lensing. We quantify the observability of the intrinsic shape and size correlations and estimate with the Fisher-formalism how well the alignment parameter can be determined from the Euclid weak lensing survey. Specifically, we find a contamination of the weak lensing convergence spectra with an intrinsic size correlation amounting to up to 10% over a wide multipole range $\ell=100\ldots300$, with a corresponding cross-correlation exhibiting a sign change, similar to the cross-correlation between weak lensing shear and intrinsic shapes. A determination of the alignment parameter yields a precision of a few percent forecasted for Euclid, and we show that all shape and many size correlations should be measurable with Euclid.
