Line Intensity Mapping with the CO Mapping Array Pathfinder - Probing Two Key Epochs in Cosmic Evolution

宇宙始于138亿年前的大爆炸。大爆炸后40万年，宇宙中没有恒星或星系，而是充满了气体——主要是氢原子。在接下来的几十亿年里，这些原子形成了第一批恒星、星系和星系群，最终形成了我们今天所看到的宇宙。我们无法看到第一批星系发出的星光，因为在这个时候，星系之间的氢原子就像雾一样。星系中一氧化碳气体发出的无线电波可以穿透迷雾。我们已经建造了一种新型的“射电相机”，并将用它来测量这些无线电波，揭开隐藏星系的面纱。这很重要，因为它将改变我们对恒星和星系在宇宙时间内形成方式的理解，并有助于训练下一代射电天文学家和仪器学家设计其他更强大的射电相机。COMAP团队将以各种形式向公众传播他们的研究结果，包括公共讲座系列、当地报纸专栏、网页、当地科学博览会、望远镜活动（如开放参观、参观和观星派对）以及美国印第安人参与的年度访问和参观。一氧化碳映射阵列探路者（COMAP）将利用一氧化碳（CO）线追踪星系中恒星形成的演化，从而打开再电离时代（EoR）和星系组装时代的新窗口。COMAP是一种开创性的仪器，它利用了一种名为“线强度映射”（LIM）的新技术，它将提供一种新的方法来研究星系在宇宙时间内的性质和演化，使用示踪剂如CO，中性氢或电离碳。第一个LIM自相关检测是触手可及的，这一提议将使COMAP在这方面处于竞争地位。COMAP第一阶段包括一个10.4米的望远镜，位于欧文斯谷射电天文台（OVRO），配备一个19像素的光谱仪阵列，将在26-34 GHz频率范围内绘制总计约16平方度的天空，光谱分辨率为2 MHz。因此，在第一阶段，COMAP对EoR时期的CO（2-1）排放和星系组合时期的CO（1-0）排放非常敏感。第一阶段的接收器已经投入使用，科学观测于2019年6月开始。这笔奖金将用于完成为期两年的观测活动，分析数据并公布结果。分析将集中在z=2.4-3.4的CO（1-0）信号上，该信号可以在高显著性下检测到。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Universe began with a Big Bang 13.8 billion years ago. 400,000 years after the Big Bang the Universe had no stars or galaxies, but was filled with gas - mostly hydrogen atoms. Over the next few billion years these atoms formed themselves into the first stars, galaxies and groups of galaxies, eventually resulting in the kind of Universe we see around us today. We can't see the starlight from these first galaxies because at this time the hydrogen atoms between the galaxies acted as a kind of fog. Radio waves from carbon monoxide gas in the galaxies can pierce the fog. We have built a new kind of 'radio camera' and will use it to measure these radio waves and unveil the hidden galaxies. This is important because it will transform our understanding of the way stars and galaxies formed over cosmic time and help train the next generation of radio astronomers and instrumentalists designing other more powerful radio cameras. The COMAP team will communicate their results to the public in a variety of formats including a public lecture series, a local newspaper column, web pages, local science fairs, activities at the telescope (e.g. open house, tours and star-gazing parties) and an annual visit and tour for the United American Indian Involvement.The CO Mapping Array Pathfinder (COMAP) will open new windows on both the Epoch of Reionization (EoR) and the Epoch of Galaxy Assembly by using carbon monoxide (CO) lines to trace the evolution of star formation in galaxies through these two important epochs. COMAP is a pioneering instrument that exploits a novel technique called "Line Intensity Mapping" (LIM), which will provide a new way to study the properties and evolution of galaxies over cosmic time, using tracers such as CO, neutral hydrogen or ionized carbon. The first LIM auto-correlation detection is within reach and this proposal will put COMAP in a competitive position in this regard. COMAP Phase I comprises a 10.4-m telescope, located at the Owens Valley Radio Observatory (OVRO), equipped with a 19-pixel spectrometer array that will map a total of about 16 square degrees of sky in the frequency range 26-34 GHz, with spectral resolution of 2 MHz. In Phase I, COMAP is thus sensitive to CO(2-1) emission from the EoR and CO(1-0) emission from the epoch of galaxy assembly. The Phase I receiver has been commissioned and science observing began in June 2019. This award will be used to complete a 2-year observing campaign, analyze the data and publish the results. The analysis will focus on the CO(1-0) signal from z=2.4-3.4, which could be detected at high significance.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.