Intrinsic ellipticity correlations between galaxies

下一代弱透镜测量的目标是将宇宙学参数的精度限制在几个百分点，特别是它们将测量暗能量状态方程参数及其时间演化到非常高的精度。为了达到这一精度，人们需要很好地控制系统学，最重要的是对透镜星系的光度红移估计，特别是层析测量，以及模仿微弱透镜信号的本征椭圆度关联。这些内禀排列是由相邻星系角动量之间的相关性引起的，并已被证明对参数的估计有很大影响。这个项目的中心目标是通过推导高阶关联函数，通过角动量模型改善对椭圆度排列的理解，该排列与大尺度结构的潮汐场有关。此外，我们的目标是研究利用内禀椭圆度关联重建密度场的可行性，这种关联在低红移时比弱透镜诱导的密度场关联更具优势。

The next generation of weak lensing surveys will aim to constrain the cosmological parameters to an accuracy of a few percent, in particular they will measure the dark energy equation of state parameter and its time evolution to very high accuracy. In order to reach this accuracy, one needs a very good control of systematics, most importantly of the photometric redshift estimation of the lensed galaxies, in particular for tomographic measurements, and of intrinsic ellipticity correlations, which mimick the weak lensing signal. These intrinsic alignments are induced by the correlations between angular momenta of neighbouring galaxies and have been shown to affect the estimation of parameters significantly. The central goal of this project is to improve the understanding of ellipticity alignments, which are related to the tidal field of the large-scale structure by angular momentum models, by deriving higher-order correlation functions. Furthermore, we aim to investigate the feasibility of density field reconstructions using intrinsic ellipticity correlations, which were shown to dominate at low redshift over the weak lensing induced ones.