Generation and Evolution of Structures in the interstellar medium

恒星的形成与星际介质（ISM）中分子云的结构和演化密切相关。我们建议探索这一联系与一种新的方法相结合的远红外地图的尘埃（赫歇尔）和冷却线（C+与索菲亚）与分子线地图。将使用和开发专门的分析工具来分析地图，并将其与模拟进行比较，以确定潜在的物理过程。这一联合项目依靠科隆KOSMA小组（结构识别方法和索菲亚）、波尔多LAB星星形成小组（赫歇尔和光谱成像图）和INRIA研究所波尔多GeoStat小组（复杂系统分析非线性方法专家）成员的互补专长。为了理解恒星的起源，有必要理清重力、湍流、磁场以及从弥漫气体到分子云和坍缩核心的辐射的相对重要性，并研究细丝的作用。使用GeoStat团队开发的创新分析工具，我们将分析赫歇尔图像以及来自地面望远镜的新光谱成像调查，以及使用索菲亚的THz光谱。与模拟云的类似分析的比较将使我们能够导出解释云演化和致密结构形成的基本物理过程。我们选择的模板云，涵盖了质量，温度和恒星形成活动的代表性参数空间，以测试不同的演化阶段和恒星形成云的多样性。与科隆集团的密切合作是必要的，以受益于他们的长期专业知识，量化云结构（如三角洲方差）和统计措施（如N-PDF），这些创新的方法和分析工具，将开发由波尔多合作伙伴（实验室）在跨学科的努力与GeoStat一起。我们还将探索湍流与加热和冷却过程的耦合，从而导致结构变化，这可能有助于我们提高对反馈调节星星形成效率的作用的理解。更确切地说，我们的目标是确定从原子到分子氢的过渡阶段的空间尺度，在确定的位置的湍流耗散和洞察到其他结构的生成过程。该项目的目标不是在3年内全面了解星星的形成，但它是向前迈出的重要一步，因为它将系统地利用大量现有但尚未充分利用的档案数据、精心挑选的新观测数据以及分析和解释数据的先进工具。因此，它将为分子云和恒星的形成提供新的线索，并可能成为许多研究的起点。

The formation of stars is intimately linked to the structure and evolution of molecular clouds in the interstellar medium (ISM). We propose to explore this link with a new approach by combining far-infrared maps of dust (Herschel) and cooling lines (C+ with SOFIA) with molecular line maps. Dedicated analysis tools will be used and developed to analyse the maps and compare them to simulations in order to identify for the underlying physical processes. This joint project relies on the complementary expertise of the members of the Cologne KOSMA group (structure identification methods and SOFIA), the Bordeaux LAB star formation group (Herschel and spectro-imaging maps) , and the Bordeaux GeoStat team of INRIA institute (experts in nonlinear methods for the analysis of complex systems). To understand the genesis of stars, it is necessary to disentangle the relative importance of gravity, turbulence, magnetic fields, and radiation from diffuse gas, to molecular clouds and collapsing cores, and to study the role of filaments. Using innovative new analysing tools developed by the GeoStat team, we will analyse the Herschel images as well as new spectro-imaging surveys from ground-based telescopes, and THz spectroscopy using SOFIA. The comparison with similar analysis on simulated clouds will allow us to derive the underlying physical process which explains cloud evolution and the formation of dense structures. We select template clouds that cover a representative parameter space of mass, temperature, and star-formation activity to test the different evolutionary stages and the diversity in star-forming clouds. Close collaboration with the Cologne group is required to profit from their long-lasting expertise of quantifying cloud structure (e.g. Delta-variance) and statistical measures (e.g. N-PDFs) for these innovative methods and analysis tools that will be developed by the Bordeaux partner (LAB) in an interdisciplinary effort together with GeoStat. We will also explore the coupling of turbulence with heating- and cooling processes that leads to structural changes and that may help us to improve our understanding of the role of feedbacks to regulate the star formation efficiency. More precisely we aim at identifying the spatial scales of the transition phase from atomic to molecular hydrogen, at determining the location of the dissipation of turbulence and get insight into other structure generating processes. The project does not aim at a full understanding of star formation within 3 years, but it constitutes an important step forward as it will make systematic use of a wealth of existing, yet not fully exploited archival data, carefully chosen new observations, and sophisticated tools to analyse and interpret the data. As such, it will shed new light on how molecular clouds and stars form and may well be the starting point for many studies to follow.