Accurate and precise statistical methods for weak gravitational lensing

引力透镜--来自遥远光源的光线被中间物质偏转--是理解我们宇宙的一项强大技术。星系形状中的相干扭曲可以用来推断介于其中的暗物质的性质，特别是它的空间分布(即它有多成团或有多光滑)及其在整个宇宙历史中的演化。透镜对时空的几何形状很敏感，因此对宇宙的组成成分也很敏感。主要成分是所谓的“暗能量”，这是一种鲜为人知的能量密度来源，它似乎模仿了爱因斯坦场方程式中的一个宇宙常数项。了解暗能量的性质是我们理解物理学的基础，也是即将进行的宇宙学调查(如欧几里得太空望远镜)的主要科学推动力之一。拥有精确和精确的技术来测量天空中透镜强度波动的功率谱，将是用欧几里得测量暗能量性质的关键。该学生将开发受宇宙微波背景分析启发的统计方法，并将它们应用于真实的宇宙切变合成地图。爱丁堡领导着欧几里德的弱透镜分析，并主办了英国科学地面部分科学数据中心。将有机会在欧几里德弱透镜团队中工作，使学生能够接触到最先进的宇宙学调查。还将有机会将这些方法应用于当前的数据。

Gravitational lensing - the deflection of light from distant luminous sources by intervening matter - is a powerful technique for understanding our Universe. Coherent distortions in the shapes of galaxies can be used to infer the properties of the intervening dark matter, in particular its spatial distribution (i.e. how clumped or how smooth it is) and its evolution throughout cosmic history. Lensing is sensitive to the geometry of space-time and hence to the constituent components of the Universe. The dominant component is the so-called "dark energy", a poorly-understood source of energy-density which appears to mimic a cosmological constant term in the Einstein field equations. Gaining an understanding into the properties of dark energy is fundamental to our understanding of physics and is one of the main science drivers for upcoming cosmology surveys such as the Euclid space telescope. Having accurate and precise techniques for measuring the power spectrum of fluctuations in the lensing strength over the sky will be crucial for measuring dark energy properties with Euclid. The student will develop statistical methods inspired by analyses of the cosmic microwave background and apply them to realistic synthetic maps of cosmic shear. Edinburgh leads the weak lensing analysis of Euclid and hosts the UK Science Ground Segment Science Data Centre. There will be the opportunity to work within the Euclid weak lensing team, giving the student access to a state-of-the-art cosmology survey. There will also be opportunities to apply the methods to current data.