"The Hidden Universe": linking the evolution of dusty star formation and gas consumption across cosmic time

宇宙中超过一半的恒星形成能量在可见光波段消失，并被吸收并重新辐射远红外/亚毫米星光的尘埃所覆盖；850和450微米的大气窗口使我们能够从星系形成和演化的“隐藏面”获得红移远红外发射。詹姆斯·克拉克·麦克斯韦望远镜（JCMT）宇宙学遗产调查（S2CLS； Geach等人，2017）及其通过SCUBA-2 COSMOS调查（S2COSMOS； Simpson等人，2017）和STUDIES （Wang等人，2017）进行的扩展是有史以来规模最大、最敏感、最雄心勃勃的850和450微米（亚毫米波段）调查。这些前所未有的遗产调查已经产生了数千个在亚毫米波段选择的高红移星系-在这些波长的先前调查中提供了一个数量级的改进！这个项目将包括测量来自遥远星系群的亚毫米辐射，不仅估计星系中模糊的恒星形成速率，而且还估计其中包含的冷气体的质量，以一种非常清晰的方式在大跨度的宇宙历史中为正在进行的恒星形成提供燃料。该项目将采用一种独特的前沿方法，将S2CLS、S2COSMOS和STUDIES2数据与非常深的光学/近红外星系目录交叉相关，探索恒星形成和气体消耗在宇宙时间内的演变，并将结果与最先进的模型（如EAGLE）进行比较。因此，一个关键的主题将包括测量ISM质量在红移中的演化，以及这是如何依赖于星系特性（如质量和环境），以及其他星系特性（如AGN活动）的。我们正在利用位于智利Chajnantor高原5000米的阿塔卡马大型毫米阵列（ALMA），以更高的分辨率对这些高z次毫米探测源进行详细的跟踪，这项工作的发现将为新的ALMA望远镜建议提供依据。也将有机会前往夏威夷的JCMT，帮助这个监督小组的天文学家领导的相关亚微米科学的观测活动。

Over half of the star formation energy generation in the Universe is extincted at optical wavelengths and enshrouded by dust which absorbs and re-radiates the starlight in the far-infrared/submm; and the 850&450um atmospheric windows allow us to access the redshifted far-infrared emission from this "hidden side" of galaxy formation and evolution. The James Clerk Maxwell Telescope (JCMT) Cosmology Legacy Survey (S2CLS; Geach et al. 2017) and its extension via the SCUBA-2 COSMOS survey (S2COSMOS; Simpson et al. 2017) and STUDIES (Wang et al. 2017) are the largest and most sensitive and ambitious surveys at 850 and 450 micron (in the submm wavebands) ever conducted. These unprecedented legacy surveys have yielded thousands of high-redshift galaxies selected in the sub millimetre wavebands - providing an order-of-magnitude improvement in the sample sizes of previous surveys at these wavelengths!This project will involve making measurements of the submm emission from distant galaxy populations to estimate not only the obscured star formation rate of the galaxies but also the mass of cold gas contained within them fuelling the on-going star formation in a remarkably clean way over a large span of cosmic history. This project will adopt a unique cutting-edge approach, cross-correlating the S2CLS and S2COSMOS and STUDIES2 data with very deep optical/near-infrared galaxy catalogues to explore the evolution of star formation and gas consumption across cosmic time and comparing the results to state-of-the-art models, such as EAGLE. A key theme will thus include measuring the evolution of the ISM mass over redshift and how this depends on galaxy properties such as mass and environment, as well as other galaxy properties like AGN activity. We are involved in ongoing efforts to perform detailed follow-up of these high-z submm-detected sources at higher resolution with the Atacama Large Millimetre Array (ALMA) situated at 5000m on the Chajnantor plateau in Chile, and the findings of this work will feed into new ALMA telescope proposals. There will also be an opportunity to travel to the JCMT in Hawaii to help out with observing campaigns for related submm science led by astronomers in this supervisory team.