Collaborative Research: Changes in Molecular Gas and Galaxy Properties Over Time in the Era of Integral Field Unit Surveys

第一部分星系性质随时间的变化是由其冷气体的数量驱动的，冷气体是恒星形成的原料。 因此，了解星系冷气成分的性质将告诉我们星星形成过程如何随时间变化，以及这如何影响星系。利用最近完成的对邻近星系样本中一氧化碳气体的调查，提议者将（1）测量分子气体是如何消耗的，以测试如何影响星系中星星的形成;（2）绘制这种气体在星系中的位置，以确定这些位置是否/如何影响星星的形成;以及（3）测量气体如何流入和流出星系，以确定这如何影响星系随时间的结构变化。 特别是，从这项研究中可以回答的一些问题包括：哪些因素影响分子气体转化为恒星？分子气体是如何构造的？星系是如何成长和衰老的？ 这一建议将提供深入了解星系形成的过程和我们对这些天体的理解。Part 2这一建议计划结合联合收割机空间分辨光谱的一氧化碳分子气体，电离气体和恒星人口的125个附近星系的样本。测量空间分辨的分子气体耗尽时间尺度作为各种星系性质的函数，使用光谱线的诊断来探测扩散的分子气体，限制这些星系的气体流入和流出速率，有可能极大地增加我们对正常星系中星星形成的理解。人们早就认识到，这些过程是由星星形成的兴衰所驱动的，而恒星形成的兴衰最终与冷气体的供应有关。然而，在理解星系中星星形成规律方面的进一步进展，需要在分子气体质量和星星形成速率之外的额外观测约束。通过利用迄今为止最大，最均匀的干涉CO星系调查的独特组合，（银河系演化河外数据库，或EDGE）和一个主要的正在进行的光学积分场单元（IFU）调查（CALIFA），项目小组将面对星星形成和星系演化的模型与气体质量和星星形成率的统一，高质量的测量，并辅以大量的额外数据，包括星星形成历史、恒星质量、核活动、气体和恒星的金属丰度和运动学。这些研究将在一个空间分辨的基础上进行，跨越一个定义明确的样本，是附近宇宙的代表，因此将告知未来的研究星星的形成和质量组装在所有红移进行的JWST和阿尔马。

Part 1Changes of a galaxy's properties over time are driven by the quantity of its cold gas, the raw material from which stars form. Thus, understanding the properties of a galaxy's cold gas component will tell us both how the star formation process changes over time and how this affects galaxies. Using a recently completed survey of carbon monoxide gas in a sample of nearby galaxies, the proposers will (1) measure how the molecular gas is used up, in order to test how star formation in the galaxies is affected; (2) map the locations of this gas in the galaxies to determine if/how these locations affect star formation; and (3) measure how the gas is flowing into and out of the galaxies to determine how this affects structural changes in the galaxies over time. In particular, some questions that can be answered from this research include: What factors affect the conversion of molecular gas into stars? How is molecular gas structured? How do galaxies grow and age? This proposal will provide insight into the process of galaxy formation and our understanding of these objects.Part 2This proposal plans to combine spatially resolved spectroscopy of carbon monoxide molecular gas, ionized gas and stellar populations for a sample of 125 nearby galaxies. Measuring spatially-resolved molecular gas depletion time scales as a function of various galaxy properties, using diagnostics of spectral lines to probe diffuse molecular gas, and constraining the rates of gas in- and outflow for these galaxies has the potential to add greatly to our understanding of star formation in normal galaxies.Observations of galaxies across a range of redshifts allow us to witness the growth and aging of the galaxy population. It has long been recognized that these processes are driven by the rise and fall of star formation, which is ultimately linked to the supply of cold gas. Further progress in understanding the regulation of star formation in galaxies, however, requires additional observational constraints beyond the molecular gas mass and star formation rate. By exploiting a unique combination of the largest, most homogeneous interferometric CO survey of galaxies to date (the Extragalactic Database for Galaxy Evolution, or EDGE) and one of the principal ongoing optical integral field unit (IFU) surveys (CALIFA), the project team will confront models of star formation and galaxy evolution with uniform, high quality measurements of gas masses and star formation rates, supplemented by a vast array of additional data, including star formation history, stellar mass, nuclear activity, and the metallicity and kinematics of the gas and stars. These studies will be conducted on a spatially resolved basis across a well-defined sample that is representative of the nearby Universe, and will thus inform future studies of star formation and mass assembly at all redshifts undertaken by JWST and ALMA.