CAREER: Towards Dark Energy -- A High-precision Drone-based Calibrator for Next-Generation 21cm Cosmology Experiments

职业：迈向暗能量——用于下一代 21 厘米宇宙学实验的高精度无人机校准器

• 批准号: 1751763
• 负责人: Laura Newburgh
• 金额: $ 46.09万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751763&HistoricalAwards=false
• 关键词: CAREER; Towards; Dark; Energy; precision

Measurements of the Universe over the last two decades have shown that nearly 75% of the Universe is made of a mysterious component: Dark Energy. Unlike "regular matter", Dark Energy seems to act against gravity and is causing the expansion of the Universe to accelerate. This is very confusing, and to explain it, we may have to re-write particle physics or perhaps even the laws of gravity. The best way to answer the question "What is Dark Energy?" is to measure the expansion of the Universe farther back in time. Recently astronomers realized that radio telescopes have the potential to make this measurement better than any other type of telescope. This has never been attempted before, and we are now building telescopes to achieve this goal. However, to be successful we need to understand the telescope "beam" (like a beam of light, a telescope points at one place and focuses there, and we must know what that beam looks like on the sky). For this CAREER grant, the PI is building radio sources to put on quadcopter drones to fly above the telescope. Using the radio telescope data, the location of the drone (with special position sensors), and some new analysis techniques, we will make a map of our telescope beam. The end result will be an important measurement that helps us understand Dark Energy better. The accelerated expansion of the Universe was discovered from supernova measurements in 1998 and no fundamental theories for this acceleration have yet been experimentally verified. As a result, cosmologists inserted a new component ("Dark Energy") into our cosmological models, but the underlying theories to explain the accelerated expansion involve either (i) a modification to General Relativity or (ii) a new particle which would predict a unique time dependence of the expansion rate. Either would revolutionize our current models of fundamental theories of physics. To answer these questions we must measure the expansion history of the Universe across the past 11 billion years and pin down the influence of Dark Energy on the expansion. The most promising path for this comes from measurements of galaxies (measuring 100, 000 galaxies across a wide swath of the sky). Unfortunately, current and next-generation optical galaxy surveys are restricted in how far back in time they can see due to limitations in detector technology. Radio telescopes do not have these limitations, and offer a promising solution to make radio surveys of galaxies across most of cosmic time. This measurement has never been attempted before and we are now building radio telescopes designed to achieve this goal. However, we already know that to be successful we must understand our telescope characteristics extremely well, in particular the telescope "beam" (like a beam of light, a telescope points at one place and focuses there, and we must know what that beam looks like on the sky). For this CAREER grant, the PI is developing a beam mapper using a quadcopter drone. The PI's team will fly a radio source on the drone above the telescopes and use the radio data and drone position to make a map of the beam. This requires developing a stabilized noise source to be flown on the drone, improved sensors for better drone position accuracy, and new analysis techniques - particularly a mathematical transformation to use measurements made near the dish and infer what they look like on the sky. The end result will be an important measurement for cosmology radio telescopes and a beam mapping technique that is demonstrated to work at the high precision required for Dark Energy science goals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在过去的二十年中，宇宙的测量表明，将近75％的宇宙是由神秘的组成部分组成的：深色能量。与“常规物质”不同，暗能量似乎对重力作用，并导致宇宙的扩张加速。这是非常令人困惑的，要解释它，我们可能必须重新编写粒子物理学甚至重力定律。回答“什么是黑能？”这个问题的最佳方法。是为了及时衡量宇宙的扩展。最近，天文学家意识到，射电望远镜具有比任何其他类型的望远镜更好的方法。以前从未尝试过，我们现在正在构建望远镜以实现这一目标。但是，要取得成功，我们需要了解望远镜的“光束”（就像光束一样，望远镜指向一个位置并集中在那里，我们必须知道天空上的光束是什么样）。对于这项职业赠款，PI正在建造无线电来源，以乘坐四轮驱动器无人机飞行望远镜。使用射电望远镜数据，无人机的位置（带有特殊位置传感器）以及一些新的分析技术，我们将为望远镜梁制作地图。最终结果将是一个重要的测量，可以帮助我们更好地理解黑暗能量。从1998年的超新星测量结果发现了宇宙的加速扩张，并且尚未对这种加速度的基本理论进行实验验证。结果，宇宙学家将一个新组件（“暗能能”）插入我们的宇宙学模型中，但是解释加速膨胀的基本理论涉及（i）对一般相对性的修改，或者（ii），或（ii）一个可以预测一个新粒子扩展率的独特时间依赖性。两者都会彻底改变我们当前的物理基本理论模型。为了回答这些问题，我们必须在过去的110亿年中衡量宇宙的扩张历史，并确定黑暗能源对扩张的影响。最有希望的路径来自星系的测量值（在天空的巨大片段中测量100，000个星系）。不幸的是，由于探测器技术的限制，当前和下一代光学银河系调查限制了它们可以看到的距离。射电望远镜没有这些局限性，并提供了有希望的解决方案，可以在大部分宇宙时间内对星系进行无线电调查。这种测量以前从未尝试过，我们现在正在构建旨在实现此目标的射电望远镜。但是，我们已经知道，要取得成功，我们必须非常了解我们的望远镜特征，尤其是望远镜“光束”（像光束一样，望远镜，望远镜点在一个地方并聚焦在那里，我们必须知道光束的外观喜欢在天空上）。对于这项职业赠款，PI正在使用四轮驱动器无人机开发横梁映射器。 PI的团队将在望远镜上方的无人机上驾驶无线电源，并使用无线电数据和无人机位置来制作梁的地图。这需要开发一个稳定的噪声源，要在无人机上飞行，改进的传感器以提高无人机位置精度，并进行新的分析技术 - 尤其是一种数学转换，以使用盘子附近进行的测量并推断它们在天空上的外观。最终结果将是对宇宙学射程望远镜的重要衡量标准和一项光束映射技术，该技术被证明是在黑暗能源科学目标所需的高精度上起作用的。该奖项反映了NSF的法定任务，并被认为是通过使用评估来支持的。基金会的智力优点和更广泛的影响评论标准。