Seeing Dark Matter with Weak Gravitational Lensing

暗物质（DM）是宇宙中物质的主要形式，但由于难以直接测量其性质，从经验上对其了解甚少。了解暗物质及其与可见物质的联系对于解开星系形成之谜也至关重要，因为暗物质形成了星系可见部分形成和演化的光晕和细丝的结构框架。******弱引力透镜（WL）已经成为测量暗物质数量和空间分布的最有希望的方法之一。加拿大-法国成像巡天（CFIS）在将WL与星系光谱红移结合起来的科学研究方面具有非凡的能力（由于它与斯隆数字巡天重叠）。这种WL和光谱学的结合在国际背景下是独一无二的，并且可以研究暗物质，这是其他调查无法实现的。我是CFIS r-band （WL）组件的首席科学家，也是CFIS国际WL团队的负责人。******这个建议有两个主要的科学目标。第一个目标是绘制和描述晕状和细丝状暗物质结构的精细细节。为了实现这些目标，我的团队将使用CFIS数据来研究以前未被探索过的密度或环境中的暗物质结构：(1)在星系之间，以宇宙网细丝的形式；(3)暗物质晕的形状及其与大尺度环境的关系。******第二个目标是在大尺度上测试广义相对论（GR）和宇宙模型。我的小组将比较光的偏转与星系落入结构：通过将CFIS WL与SDSS红移数据相结合，我们将进行迄今为止最严格的测试。我们将通过对大尺度结构和特殊速度的比较，在最大尺度和附近的宇宙中测量物质、星系和引力之间的关系。******WL是数十亿美元规模项目（欧几里得卫星，大型综合巡天望远镜）背后的推动者，这些项目承诺在本世纪20年代早期到中期开始时，透镜功率将增加几个数量级。通过CFIS获得的经验将使我的团队处于一个特殊的位置，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.