Seeing Dark Matter with Weak Gravitational Lensing

暗物质(DM)是宇宙中物质的主要形式，但由于直接测量其性质的困难，经验上对它的了解仍然很少。对DM及其与可见物质的联系的理解对于解开星系形成的谜团也是至关重要的，因为DM形成了光晕和细丝的结构框架，星系的可见部分在其中形成和演化。弱引力透镜(WL)已成为测量暗物质数量和空间分布的最有前途的方法之一。加拿大-法国成像勘测(CFIS)在将WL与星系光谱红移相结合的科学方面拥有非凡的力量(因为它与斯隆数字天空勘测重叠)。WL和光谱学的这种结合在国际范围内是独一无二的，它允许对暗物质的研究，这是其他任何调查都无法实现的。我是CFIS R波段(WL)组件的首席科学家，也是CFIS国际WL团队的领导。*这项提议有两个主要的科学目标。第一个目标是绘制和描述光晕和灯丝中暗物质结构的精细细节。为了实现这些目标，我的团队将利用CFIS数据来研究以前未被探索的密度或环境区域中的暗物质结构：(1)在星系之间，以宇宙网的丝状形式；(2)在潮汐剥离的卫星光晕中；(3)暗物质晕的形状及其与大型环境的联系。*第二个目标是在大尺度上测试广义相对论(GR)和宇宙学模型。我的团队将比较光线的偏转与星系进入结构的情况：通过结合CFIS WL和SDSS红移数据，我们将进行迄今为止最严格的测试。我们将通过大尺度结构和特殊速度的比较，在最大尺度上和邻近宇宙中测量物质与星系和引力之间的关系。*WL是数十亿美元规模项目(欧几里德卫星、大型天气观测望远镜)的推动者，这些项目承诺在本世纪20年代初至中期开始时，透镜功率将增加数量级。通过CFIS获得的经验将使我的团队处于特殊的地位，可以在这个弱引力透镜的新黄金时代利用这些新的调查。

Dark matter (DM) is the dominant form of matter in the Universe, yet it remains poorly understood empirically due to the difficulty in directly measuring its properties. An understanding of DM and its link to visible matter is also critical for disentangling the puzzles of galaxy formation, since DM forms the structural framework of halos and filaments within which the visible parts of galaxies form and evolve. ******Weak gravitational lensing (WL) has emerged as one of the most promising ways to measure the quantity and spatial distribution of dark matter. The Canada-France Imaging Survey (CFIS) has exceptional power (due to its overlap with the Sloan Digital Sky Survey) for science that combines WL with galaxy spectroscopic redshifts. This combination of WL and spectroscopy is unique in the international context and allows studies of dark matter that no other survey can achieve. I am the Lead Scientist of the r-band (WL) component of CFIS, and lead of the international CFIS WL team.******This proposal has two primary scientific objectives. The first objective is to map and characterize the fine details of dark matter structure in haloes and filaments. To meet these goals, my group will use CFIS data to study the dark matter structures in previously unexplored regimes of density or environment: (1) in between galaxies, in the form of filaments of the cosmic web; (2) in tidally stripped halos of satellites (3) the shapes of dark matter haloes and their connection to the large-scale environment.******The second objective is to test General Relativity (GR) and the cosmological model on large scales. My group will compare the deflection of light with the infall of galaxies into structures: by combining CFIS WL with SDSS redshift data, we will perform the most stringent test to date. We will measure the relationship between matter and galaxies and gravity on the largest scales and in the nearby Universe through comparisons of large-scale structure and peculiar velocities. ******WL is the driver behind several billion dollar scale projects (the Euclid satellite, the Large Synoptic Survey Telescope), which promise orders of magnitude increases in lensing power when they begin in the early-to-mid 2020s. The experience gained through CFIS will put my group in an exceptional position to exploit these new surveys in this new golden age of weak gravitational lensing.