Understanding of the dark side of the universe with weak gravitational lensing

宇宙学是研究宇宙大尺度结构的天体物理学的一个分支。它关注的是关于它的形成、演变和命运的基本问题。自从80年前埃德温·哈勃发现宇宙在膨胀以来，我们对宇宙的认识大大加深了。天文学家现在对宇宙的物理成分，它是如何达到现在的状态，以及它的未来会是什么样子，有了相当准确的认识。然而，尽管精确的观测越来越多，大爆炸理论的丰富细节现在可以在专家之间讨论，我们对宇宙的认识对现代物理学提出了巨大的挑战：宇宙中90%以上的物质是不可见的，目前归因于一种新的物质类型，其物理性质仍然完全未知，宇宙的膨胀似乎是由一种“流体”驱动的，其性质也未知。我们正处于一场新的“哥白尼式”革命的边缘吗？这些所谓的“暗物质”和“暗能量”成分塑造了我们今天所看到的宇宙。我的研究重点是利用一种基于引力透镜效应的新技术来观测和解释暗物质和暗能量的分布。正如爱因斯坦80年前所预测的那样，经过大质量物体附近的光被偏转的程度与偏转器的质量成正比。引力透镜可以用来测量引起光偏转的质量。我正在利用这种效应来追踪、绘制和量化宇宙中暗物质的分布，这是唯一能“直接”看到它的方法。这项研究的影响将导致对结构形成的阴暗面的理解，即从真正的直接观察暗物质而不是间接的猜测。物理学家和天体物理学家都对这个话题感兴趣：他们面临的挑战之一是理解这种新型物质的本质。

Cosmology is the branch of astrophysics which studies the large scale structures of the Universe. It is concerned with fundamental questions about its formation, evolution and its fate. Since the discovery made by Edwin Hubble eighty years ago that the Universe is expanding, our picture of it has considerably deepened. Astronomers have now a fairly accurate idea of the physical content of the Universe, how it reached its current state, and what will its future be. However, despite the increasing number of accurate observations, and the richness of details the Big-Bang theory can now discussed among specialists, our knowledge of the Universe poses a great challenge to modern physics: more than 90 percents of matter in the Universe is not visible, it is currently attributed to a new type of matter, which physical nature remains totally unknown, and the expansion of the Universe seems to be driven by a"fluid" whose nature is also unknown. Are we on the verge of a new "Copernician" revolution? These so called "dark matter" and "dark energy" components have shaped the Universe we see today. My research focuses on the observation and the interpretation of the dark matter and dark energy distribution using a novel technique based on the gravitational lensing effect. As A. Einstein predicted eighty years ago, the light passing nearby a massive body is deflected in proportion of the mass of the deflector. Gravitational lensing can be used to measure the mass responsible for the light deflection. I am using this effect to trace, map and quantify the dark matter distribution in the Universe, which is the only way to see it "directly". The impact of this research will lead to the understanding the dark side of structure formation, i.e. from real direct observation of dark matter instead of indirect/speculations about it. Both physicists and astrophysicists have an interest in this topic: one of their challenges is to understand the nature of this new type of matter.