LADUMA: Reaching the Highest Redshifts with the Deepest HI Survey

LADUMA：通过最深入的 HI 调查达到最高的红移

• 批准号: 2308161
• 负责人: Andrew Baker
• 金额: $ 39.16万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308161&HistoricalAwards=false
• 关键词: LADUMA; Reaching; Highest; Redshifts; Deepest

Since their formation in the early universe, galaxies have been converting their gas reservoirs - almost entirely composed of atomic (HI) and molecular hydrogen (H2) - into stars. Astronomers have formed an impressively detailed picture of this process, including the "hydrogen cycle" by which atomic and molecular gas transition from one form to the other and back again. The study of H2 in extremely distant (z 3) galaxies has been revolutionized by the Atacama Large Millimeter Array (ALMA), which takes advantage of highly luminous "tracer" molecules like carbon monoxide (CO). To probe the HI content of galaxies astronomers must rely on the much weaker 21 cm "spin-flip" transition of HI, which has effectively restricted studies to the local (z 0.2) universe. This project's goal is to extend this HI census in galaxies to the unprecedented redshift of z = 1.45 and fill a crucial gap in our current understanding of HI’s role in galaxy evolution through the Looking At the Distant Universe with the MeerKAT Array (LADUMA) survey. The project, jointly led by the PI, has been awarded 3,424-hours of high-priority time with the 64-element MeerKAT radio telescope in South Africa to image a single ultra-deep pointing in the Extended Chandra Deep Field South. Supporting observations will be used to allow HI "stacking" observations as well as discriminating HI from OH megamaser emission. All survey data will be publicly released. This project will allow continued U.S. leadership in Square Kilometer Array (SKA) precursor science. The award will also support the training of a graduate student in cutting-edge science as well as a new outreach program to community colleges in New Jersey. Results will be derived from both direct HI spectral line detections and by “stacking” samples of galaxies with previously measured positions and redshifts. The latter will allow LADUMA to achieve its full potential for studying HI out to z = 1.45, at least in a statistical sense. The project also encompasses the identification of OH megamaser “interlopers” in the HI sample that will be used to trace the cosmic history of gas-rich mergers out to z = 1.86. These research activities will benefit from detailed comparisons to theoretical models and are well-matched to the “cosmic ecosystems” theme of the recently released Astro2020 Decadal Survey on Astronomy and Astrophysics, including that theme’s priority science area (“unveiling the hidden drivers of galaxy growth”), a science question (“How do gas, metals, and dust flow into and out of galaxies?”), as well as a critical discovery area prioritized for galaxy evolution research (“mapping the circumgalactic medium and the intergalactic medium in emission”).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.

由于它们在早期宇宙中的形成，因此星系一直在将其气体储层转化为几乎完全由原子（HI）和分子氢（H2）组成的恒星。天文学家已经形成了这一过程的令人印象深刻的详细图片，包括原子和分子气体从一种形式到另一种形式的“氢循环”。 Atacama大毫米阵列（ALMA）对H2的研究进行了彻底改变，该阵列利用了一氧化碳（CO）等高度发光的“示踪剂”分子。为了探测星系的HI含量，天文学家必须依赖于HI的21 cm“ Spin-Flip”过渡，后者有效地将研究限制为局部（z 0.2）宇宙。该项目的目标是将该星系中的HI人口普查扩展到Z = 1.45的前所未有的红移，并通过使用Meerkat Array（LaDuma）调查的遥远的宇宙来填补我们当前对HI在银河发展中的作用的关键空白。该项目由PI共同领导，已获得3,424小时的高优先级时间，而南非的64个元素Meerkat射电望远镜则在Chandra Deep Field South的扩展中表现出一个非常深的指向。支持观察结果将用于允许HI“堆叠”观察结果，并将HI与OH Megamaser发射区分开。所有调查数据将公开发布。该项目将允许在平方公里阵列（SKA）前体科学中继续美国领导。该奖项还将支持对新泽西州社区大学的尖端科学研究生以及新的外展计划的培训。结果将源自两个直接的HI光谱线检测，并通过具有先前测量的位置和红移的星系“堆叠”样本。后者将使Laduma至少在统计意义上，使Laduma能够实现其学习HI到Z = 1.45的全部潜力。该项目还涵盖了HI样本中OH Megamaser“闯入者”的识别，该项目将用于跟踪Z = 1.86的气体富合并的宇宙历史。这些研究活动将受益于与理论模型的详细比较，并与最近发布的有关天文学和天体物理学的Astro2020年代际际交往调查的“宇宙生态系统”主题恰好，包括该主题的优先科学领域（包括“隐藏的星系增长驱动因素）”（“隐藏的星系驱动因素”（“隐藏的驱动因素）”，“是一个科学问题”，“众所周知”，以及众所周知的探索和探索，以及一定的探索，以及传统的探索）？对银河进化研究的优先级（“在排放中绘制电路型培养基和播层间介质”）。该奖项反映了NSF的法定任务，并通过评估基金会的智力优点和更广泛的影响来评估诚实的支持。