Collaborative Research: Observing the Cosmic Evolution of Neutral Hydrogen

氢是宇宙中最丰富的元素，因此中性氢原子是星系中星际气体的重要成分，也是最具挑战性的研究之一。中性氢发射的微弱意味着它只能通过用大型望远镜进行长期观测才能在附近宇宙以外的地方被探测到。一台灵敏度更高的新望远镜Meerkat阵列将研究星系的中性气体储藏在宇宙历史的三分之二(即最后90亿年的宇宙时间)上是如何演变的。它将决定星系的中性原子氢含量与恒星的性质、环境和宇宙纪元之间的关系。这将与理论预测进行比较，以了解气体如何流入和流出星系，并在星系内部形成新的恒星。这项研究将支持四所大学的研究生和本科生的培训；研究生将获得额外的计算和统计、研究指导、STEM学科教育以及与不同受众接触的经验。这项调查将探索排放中的中性氢(HI)，z=1.45的前所未有的高红移。单独的和堆叠的HI探测的组合，加上理论模型、多波长观测和丰富的z=0参考数据集，将探索(I)重子Tully-Fisher关系，(Ii)HI质量函数，和(Iii)星系HI含量对恒星和暗物质性质的依赖关系的演化。哦，在Meerkat的数据中被检测到的强谱线发射体的超级激光将被用来限制富含气体的星系合并的宇宙历史。HI调查数据和用于提供学生培训的教学模块都将作为该项目的一部分公开发布。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Hydrogen is the most abundant element in the universe, and neutral hydrogen atoms are thus an important constituent of interstellar gas in galaxies, but also one of the most challenging to study. The faintness of neutral hydrogen emission means that it can only be detected beyond the nearby universe via long observations with large telescopes. A new telescope with improved sensitivity, the MeerKAT array, will examine how galaxies' neutral gas reservoirs have evolved over two thirds of the universe's history (i.e., the last nine billion years of cosmic time). It will determine how galaxies' neutral atomic hydrogen content relates to the properties of their stars, their environments, and their cosmic epochs. This will be compared with theoretical predictions in order to understand how gas flows into and out of galaxies and forms new stars while inside galaxies. The research will support the training of graduate and undergraduate students at the four universities; graduate students will gain additional experience in computation and statistics, research mentorship, education in STEM disciplines, and outreach to a variety of audiences.This survey will probe neutral hydrogen (HI) in emission to an unprecedentedly high redshift of z = 1.45. The combination of individual and stacked HI detections, complemented by theoretical modelling, multiwavelength observations, and a rich z = 0 reference dataset, will probe the evolution of (i) the baryonic Tully-Fisher relation, (ii) the HI mass function, and (iii) the dependence of galaxies' HI content on stellar and dark matter properties. OH megamasers detected as strong line emitters in the MeerKAT data will be used to place constraints on the cosmic history of gas-rich galaxy mergers. Both the HI survey data and the instructional modules used to provide student training will be publicly released as part of this project.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.