Measuring Dark Energy Properties with 3D Weak Lensing

为了解决宇宙学中最重要的问题，需要最好和最全面的数据分析方法。引力透镜效应，即光子因大质量物体的存在而局部扭曲时空而偏离直线路径的效应，被广泛认为是这样一种方法。爱因斯坦预言的这一现象导致了1919年广义相对论被接受为我们的经典引力理论。现在，在这一发现近100年后，这种同样的现象适用于宇宙大尺度结构对光的透镜效应，作为距离或回顾时间的函数，使我们能够绘制宇宙的3D暗物质结构及其膨胀历史。这种透镜信息和距离的组合被称为3D弱透镜这个博士项目将建立在这个基础上，并将最好的分析方法应用于最好的数据。需要开发3D弱透镜有几个原因：1）需要包括新的理论模型，特别是引力修正的参数化，它扩展了广义相对论，包括解释暗能量的潜在机制2）系统效应，特别是那些由星系排列引起的效应，可以模拟微弱的透镜效应信号，需要包括在内。如果没有这些改进，3D弱透镜无法充分发挥其潜力。这个博士将应用这些新的发展，最先进的引力透镜数据集：154平方度CFHTLenS调查已经可用，1500平方度ESO KiDS调查正在观察数据。此外，3D弱透镜CMB互相关统计将进行调查，目的是将其应用到KiDS和普朗克。最后，该项目将建立分析工具，预计将用于即将进行的欧空局欧几里得使命，其中MSSL具有主导作用。为了确保成功的博士学位，该项目包含理论，模拟和数据分析元素，这些元素是灵活的，以便它们能够适应学生的技能和专业知识。

To address the most important questions in cosmology requires the best and most comprehensive data analysis methods. Gravitational lensing, the effect whereby photons are deflected from a straight-line path by the presence of a massive object distorting spacetime locally, is widely accepted to be such a method. This phenomenon, predicted by Einstein, led to the acceptance of General Relativity as our canonical theory gravity in 1919. Now, almost 100 years after this discovery this same phenomenon applied to the lensing of light by large-scale structures of the Universe, as a function of distance or look-back time, enables us to map the 3D dark matter structure of the Universe as well as its expansion history. This combination of lensing information and distance is known as 3D weak lensing this PhD project will build on this foundation, and apply the best analysis methods to the best data available.Development of 3D weak lensing is required for several reasons 1) new theoretical models need to be included, in particular parameterizations of modifications of gravity that extend General relativity to include a potential mechanism to explain dark energy 2) systematic effects, in particular those caused by the alignment of galaxies, that can mimic the weak lensing signal, need to be included. Without these improvements 3D weak lensing cannot reach its full potential.This PhD will apply these new developments the state-of-the-art gravitational lensing data sets: the 154 square degree CFHTLenS survey which is already available and the 1500 square degree ESO KiDS survey that is observing data now. In addition 3D weak lensing-CMB cross correlation statistics will be investigated with an aim to apply this to KiDS and Planck. Finally, this project will build the analysis tools expected to be used in the upcoming ESA Euclid mission in which MSSL has a leading role. In order to ensure a successful PhD this project contains theoretical, simulation and data analysis elements that are flexible such that they can fit with the students skills and expertise.