The Onset of Star-Formation Quenching in Massive Galaxies in the Early Universe

在宇宙诞生30亿年时，恒星形成的速度达到了顶峰。奇怪的是，当你回顾更久远的时间，当宇宙只有10 - 20亿年的时候，一些星系似乎已经完成了它们的成长，变得非常巨大，几乎没有正在形成的恒星。芬克尔斯坦和他的团队将利用斯皮策/霍比-埃伯利望远镜暗能量实验探索大区域（SHELA）调查的数据，发现并分类5000- 10000个大质量星系，并量化有多少是静止的。为了研究为什么这些星系会有如此短暂而有效的增长，研究小组将与模拟进行详细的比较，破译哪一种物理过程的组合再现了观测结果。一群本科生将与研究生配对，组成德克萨斯大学奥斯汀分校的第一个垂直整合项目团队。中学教师将在麦克唐纳天文台参加一个住宿工作坊，在这个为期三年的项目中，约有4,500名学生通过课堂活动了解这项研究。23平方度的SHELA调查包括Cerro Tololo美洲天文台/暗能量相机的光学成像(ugriz的5西格玛深度=25-26.5 AB等；Y=22)，基特峰国家天文台Mayall 4米望远镜/国家光学红外天文研究实验室的极宽视场红外成像仪（K=23）和可见光和红外天文巡天望远镜（J=21.3， K=20.9）的近红外成像，斯皮策/红外阵列相机（[3.6],[4.5]= 22.3等）的中红外成像，以及钱德拉x射线天文台和赫歇尔空间天文台的亚毫米x射线覆盖。芬克尔斯坦和他的团队将利用这一数量级的样本量增加来i)发布3z5大质量（log M/Msol 11）星系的多波长光度目录，对泊松和宇宙方差都很强大；Ii)测量静止部分作为恒星质量和红移的函数；iii)使用阿塔卡马大型毫米/亚毫米阵列和凯克/多目标红外探测光谱仪进行光谱观测，对静止星系样本中的污染率进行关键分析；iv)将数据与多个理论模拟进行比较，以探索哪种模拟最符合观测结果。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 rate of star formation peaked when the Universe was 3 billion years old. Curiously, when you look back even further in time, when the Universe was only 1-2 billion years old, some galaxies have seemingly already completed their growth, becoming very massive, with little ongoing star formation. Finkelstein and his team will use data from the Spitzer/Hobby-Eberly Telescope Dark Energy Experiment Exploratory Large Area (SHELA) survey to discover and catalog 5000-10,000 massive galaxies and quantify how many are quiescent. To investigate why these galaxies had such a short and effective growth spurt the team will make a detailed comparison to simulations, deciphering which combination of physical processes reproduce the observations. A cohort of undergraduate students will be paired with graduate students to form the first Vertically Integrated Project Team at UT Austin. Secondary school teachers will attend a residential workshop at McDonald Observatory, resulting in ~4,500 students learning about this research through classroom activities during this 3-year project. The 23 square degree SHELA survey consists of optical imaging from the Cerro Tololo Inter-American Observatory/Dark Energy Camera (5-sigma depths of ugriz=25-26.5 AB mag; Y=22), near-infrared imaging from the Kitt Peak National Observatory Mayall 4 m Telescope/National Optical-Infrared Astronomy Research Laboratory’s Extremely Wide-Field Infrared Imager (K=23) and the Visible and Infrared Survey Telescope for Astronomy (J=21.3, K=20.9), mid-infrared imaging from Spitzer/Infrared Array Camera ([3.6], [4.5]= 22.3 mag), as well as coverage in the X-rays from the Chandra X-ray Observatory and sub-millimeter from the Herschel Space Observatory. Finkelstein and his team will leverage this order of magnitude increase in sample size to i) publish a multi-wavelength photometric catalog of massive (log M/Msol 11) galaxies at 3z5, robust against both Poisson and cosmic variance; ii) measure the quiescent fraction as a function of stellar mass and redshift; iii) perform a critical analysis of contamination rates in the quiescent galaxy sample using spectroscopic observations with the Atacama Large Millimeter/submillimeter Array and the Keck/Multi-Object Spectrometer For Infra-Red Exploration, and iv) compare the data to multiple theoretical simulations to explore which simulation best matches the observations.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.