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

合作研究：整体野外单元巡天时代分子气体和星系特性随时间的变化

• 批准号: 1616199
• 负责人: Tony Wong
• 金额: $ 26.77万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1616199&HistoricalAwards=false
• 关键词: Collaborative; Research; Changes; Molecular; Gas

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.

第 1 部分 星系特性随时间的变化是由其冷气体的数量驱动的，冷气体是形成恒星的原材料。 因此，了解星系冷气体成分的特性将告诉我们恒星形成过程如何随时间变化以及这如何影响星系。利用最近完成的对附近星系样本中一氧化碳气体的调查，提议者将（1）测量分子气体的消耗情况，以测试星系中恒星形成的影响； (2) 绘制该气体在星系中的位置，以确定这些位置是否/如何影响恒星形成； （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，这项研究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？分子气体的结构如何？星系如何生长和衰老？ 该提案将深入了解星系形成的过程以及我们对这些天体的理解。第 2 部分该提案计划将一氧化碳分子气体、电离气体和恒星群的空间分辨光谱结合起来，以获取 125 个附近星系的样本。测量空间分辨分子气体耗尽时间尺度作为各种星系特性的函数，使用谱线诊断来探测扩散分子气体，并限制这些星系的气体流入和流出速率，有可能极大地增进我们的理解正常星系中恒星形成的过程。对一系列红移范围内的星系进行观测使我们能够目睹星系种群的增长和老化。人们早就认识到，这些过程是由恒星形成的兴衰驱动的，而恒星形成最终与冷气体的供应有关。然而，要进一步了解星系中恒星形成的调控，还需要分子气体质量和恒星形成速率之外的额外观测约束。通过利用迄今为止最大、最均匀的星系干涉 CO 巡天（星系演化数据库，即 EDGE）和主要正在进行的光学积分现场单元 (IFU) 巡天 (CALIFA) 之一的独特组合，项目团队将通过统一、高质量的气体质量和恒星形成速率测量来面对恒星形成和星系演化模型，并辅以大量附加数据，包括恒星形成历史、恒星质量、核活动以及金属丰度和气体和恒星的运动学。这些研究将在代表附近宇宙的明确定义样本的空间分辨率基础上进行，从而为 JWST 和 ALMA 进行的所有红移处的恒星形成和质量聚集的未来研究提供信息。