Quantifying ISM Turbulence in Nearby Galaxies on 100 pc Scales

几十年来，星际湍流的起源一直是个谜。在巨大的原子复合物（~ 100pc）及以下的尺度上研究驱动星系星际介质（ISM）湍流的可能机制是众多理论研究的重点，也是新安装的ISM - spp的核心。然而，尽管湍流是需要建模的ISM的基本属性，但在感兴趣的空间尺度上，明显缺乏观测数据来约束附近星系的代表性样本中的湍流。这个项目的目标在原则上很简单：在~ 100pc的尺度上测量星际湍流及其对当地环境的依赖，利用(a)三个最新可用的最先进的大型VLA HI对附近星系的调查（总共超过100个星系拥有精美的可用HI数据），(b)新开发的制图程序，大大增强了无线电干涉成像的动态范围。所提出的分析和(c)需要一个复杂的工具箱，需要超越以往的湍流研究。PI为该分析所需的基础工作（a-c点）做出了重大贡献，并要求为该项目提供3年的博士学位资助。这项研究的结果，在100多个河外环境的大样本中可靠地量化了100个尺度上的湍流，将与ISM - spp中许多正在进行的理论和数值ISM研究直接相关。

The origin of interstellar turbulence has been a puzzle for decades. Investigating the possible mechanisms that drive the turbulence in the interstellar medium (ISM) of galaxies on scales of giant atomic complexes (∼100 pc) and below are the focus of numerous theoretical studies and lies at the heart of the newly installed ISM–SPP. However, even though turbulence is a fundamental property of the ISM that needs to be modeled, there is a clear lack of observational data to constrain turbulence in a representative sample of nearby galaxies on the spatial scales of interest. The goal of this project is in principle simple: to measure interstellar turbulence and its dependence on local environment on scales of ∼100pc, capitalizing on (a) three newly available state–of–the–art large VLA HI surveys of nearby galaxies (totaling more than 100 galaxies with exquisite available HI data), (b) newly developed mapping routines that greatly enhance the dynamic range in radio interferometric imaging, critically needed for the proposed analysis and (c) a sophisticated toolbox that is needed to go beyond previous turbulence studies. The PI has contributed significantly to the groundwork needed for this analysis (points a–c) and requests 3 years of funding for one PhD position for this project. The results of this study, quantifying turbulence on 100 pc scales reliably in a large sample of more than 100 extragalactic environments, will be of direct relevance to many ongoing theoretical and numerical ISM studies within the ISM–SPP.