The Role of the Multi-Phase Interstellar Medium in Star Formation: From Clouds to Galaxies

多相星际介质在恒星形成中的作用：从云到星系

• 批准号: 410412113
• 负责人: Professor Dr. Frank Bigiel
• 金额: --
• 依托单位: Max-Planck-Institut für Astronomie (MPIA)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410412113?language=en
• 关键词: Role; Multi; Phase; Interstellar; Medium

The collaboration between research groups located at the Purple Mountain Observatory (PMO), the Center for Astronomy at the University of Heidelberg (ZAH) and the Max-Planck Institute for Astronomy (MPIA) in Heidelberg will characterise the physical conditions of the star forming, molecular gas and their relation to the star formation process exploiting new, comprehensive data sets defining the state-of-the-art in the field. The physical conditions of this gas remain poorly constrained in other galaxies, yet they play the key role regulating the efficiency of star formation in galaxies. This joint Chinese-German science program will address this key question via a two-pronged approach: (1) via utilising two new (sub)millimeter imaging surveys of dense molecular gas tracers in a large sample of nearby galaxies: MALATANG (currently underway at the JCMT single dish telescope and led by the Chinese group) and EMPIRE (observations finished and data are science ready) and (2) via a detailed, high-resolution case study of the physical conditions in the molecular gas on scales of individual molecular clouds in the inner part of the nearby star-forming spiral galaxy NGC6946. Our unprecedentedly rich dataset containing more than 20 molecular transitions observed from ~10 to 1mm wavelength by the VLA and PdBI interferometers opens the door for comprehensive modelling of the physical conditions and probing their respective role in regulating star formation on cloud scales. The immediate science goals are (a) to develop a general model of the physical conditions probed by various molecular gas tracers on cloud-scales, (b) calibrate individual (or combination of very few) of these transitions to be used in a wider extragalactic context (c) to constrain the physical conditions of the high-density, imminently star forming material on cloud and galaxy scales and (d) use this information to investigate the dense molecular gas-star formation relation with respect to currently favoured theories of star formation, (e) derive more accurate luminosity to molecular gas mass conversion factors as a function of physical conditions (f) to benchmark chemical tracers for galactic shocks and (g) to build a large database of density sensitive molecular transitions for nearby galaxies. During the 3 years of this grant, we will further jointly develop a series of next generation observing proposals directly building on the results from these studies, with a focus on NOEMA and ALMA, in particular in light of China's future involvement in the former facility. The proposed project is set up with a long-term collaboration in mind, extending significantly beyond the funding period. The requested funding will allow us to merge the strong expertise regarding extragalactic ISM studies in all 3 groups, providing a powerful basis for high-impact results. This grant will jump-start this collaboration and enable frequent and close interaction of all group members in China and Germany.

位于紫金山天文台（PMO），海德堡大学天文学中心（ZAH）和海德堡马克斯普朗克天文学研究所（MPIA）的研究小组之间的合作将研究星星形成的物理条件，分子气体及其与星星形成过程的关系，利用新的，全面的数据集定义该领域的最新技术。这种气体的物理条件在其他星系中仍然没有受到很好的限制，但它们在调节星系中星星形成的效率方面发挥着关键作用。这项中德联合科学计划将通过双管齐下的方法解决这一关键问题：（1）通过利用两个新的（亚）毫米成像调查，对附近星系的大样本中的致密分子气体示踪剂进行调查：麻辣烫（目前正在JCMT单碟望远镜上进行，由中国团队领导）和EMPIRE（观察结束，数据已准备好）和（2）通过详细的，高分辨率个案研究的物理条件的分子气体的尺度上的个别分子云在内部的附近恒星形成的螺旋星系NGC 6946。我们空前丰富的数据集包含20多个分子跃迁观察到从~10毫米到1毫米波长的VLA和PdBI干涉仪打开了大门，全面模拟的物理条件和探索各自的作用，在调节星星形成云尺度。近期的科学目标是：（a）发展一个云尺度上各种分子气体示踪剂探测的物理条件的通用模型，（B）校准单个的（或极少数的组合）这些转变将用于更广泛的河外背景（c）约束高密度的物理条件，即将形成云和星系尺度上的星星的物质，以及（d）使用这些信息来研究相对于当前流行的星星形成理论的致密分子气体-星星形成关系，（e）根据物理条件推导出更准确的光度与分子气体质量的转换系数;（f）为银河系冲击的化学示踪剂设定基准;（g）建立一个关于邻近星系密度敏感分子跃迁的大型数据库。在3年的资助期内，我们将在这些研究成果的基础上，以NOEMA和阿尔马为重点，特别是考虑到中国未来对前者的参与，进一步共同开发一系列下一代观测方案。拟议项目的设立考虑到了长期合作，大大超出了资助期。所要求的资金将使我们能够合并所有3个小组关于河外ISM研究的强大专业知识，为高影响力的结果提供强有力的基础。这笔赠款将启动这一合作，并使中国和德国的所有小组成员能够进行频繁和密切的互动。