Probing the Large Scale Structure of the Universe

我提出了一个研究计划，通过对无线电和微波天空的观测，以探测和表征宇宙的大尺度结构（LSS）为中心。这项研究将探索120亿年宇宙历史中结构的发展，以回答有关我们生活的宇宙的基本问题。结构（在这种情况下，星系和星系团）是如何形成的？爱因斯坦的广义相对论能解释宇宙尺度上的引力吗？“暗能量”的本质是什么？“暗能量”是一种被提出来解释宇宙加速的负压流体。 10米南极望远镜（SPT）研究宇宙微波背景（CMB），即所谓的大爆炸的“余辉”，绘制该光与它在到达我们探测器的途中经过的所有物质的相互作用。宇宙密度的变化使这些光受到引力的透镜作用，微妙地扭曲了它们的图案，而大质量星系团中心的热的致密气体也会轻微地改变它的光谱。通过研究这些印记，我们可以了解控制结构形成的过程，比如暗能量。 加拿大氢测绘实验（CHIME）是一种新型的“数字”望远镜，它将研究中性氢的21厘米发射，直接绘制有史以来在一次调查中观察到的最大宇宙体积的结构。 CHIME并没有被物理地引导指向天空的不同部分，而是使用强大的计算后端来同时对天空中的数千个离散点进行采样。事实上，望远镜将没有移动部件，而是依靠地球的旋转来“扫描”天空，因为它在头顶上漂移。目前正在建造一个缩小规模的“探路者”，用于测试整个仪器所需的技术，并为整个仪器提供概念验证。

I propose a program of study centered on detecting and characterizing the Large Scale Structure (LSS) of the Universe through observations of the radio and microwave sky. This research will probe the development of structure over 12 billion years of cosmic history, in order to answer fundamental questions about the Universe we live in. How did structure (in this context, galaxies and clusters of galaxies) form? Does Einstein's General Relatively explain gravity on cosmic scales? What is the nature of "Dark Energy," the negative pressure fluid proposed to explain cosmic acceleration? The 10m South Pole Telescope (SPT) studies the Cosmic Microwave Background (CMB), the so-called "afterglow" of the Big Bang, mapping the interactions of that light with all the material it has passed by on its way to our detectors. Variations in the density of the universe gravitationally lens this light, subtly distorting their patterns, and hot dense gas in the center of massive galaxy clusters alter its spectrum slightly. By studying these imprints, we can learn about the processes -- such as Dark Energy -- governing structure formation. The Canadian Hydrogen Mapping Experiment (CHIME) is a novel "digital" telescope which will study 21cm emission from neutral hydrogen, directly mapping structure over the largest volume of the Universe ever observed in a single survey. Rather than being physically steered to point at different parts of the sky, CHIME uses a powerful computational backend to simultaneously sample thousands of discrete points on the sky. Indeed, the telescope will have no moving parts, instead relying on the rotation of the earth to "scan" the sky as it drifts overhead. A reduced-scale "Pathfinder" is currently under construction, to be used in testing the technologies that will be required on -- and providing a proof-of-concept for -- the full instrument.