Quantifying ISM Turbulence in Nearby Galaxies on 100 pc Scales

几十年来，星际湍流的起源一直是一个谜。调查可能的机制，驱动湍流的星际介质（ISM）的星系在巨大的原子复合体（100 pc）和以下的尺度是众多理论研究的重点，是在新安装的ISM-SPP的核心。然而，即使湍流是ISM的一个基本属性，需要进行建模，有一个明显缺乏观测数据来约束附近星系的空间尺度上的代表性样本的湍流。这个项目的目标原则上很简单：利用（a）三个最新的、最先进的、对邻近星系进行的大型VLA HI巡天，（总共有100多个星系有精确的HI数据），（B）新开发的绘图程序，大大提高了无线电干涉成像的动态范围，（c）一个复杂的工具箱，需要超越以前的湍流研究。PI为该分析所需的基础工作做出了重大贡献（a-c点），并要求为该项目的一个博士职位提供3年的资金。这项研究的结果，在100 pc尺度上可靠地量化湍流在一个大样本的100多个河外环境，将直接关系到许多正在进行的理论和数值ISM研究的ISM-SPP。

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.