The Structured Interstellar Medium: Infrared-dark clouds from Herschel to ALMA

结构化星际介质：从赫歇尔到 ALMA 的红外暗云

• 批准号: 203354420
• 负责人: Sarah E. Ragan, Ph.D.
• 金额: --
• 依托单位: Max-Planck-Institut für Astronomie (MPIA)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/203354420?language=en
• 关键词: Structured; Interstellar; Medium; Infrared; dark

Molecular gas makes up the smallest volume fraction of the phases of the interstellar medium (ISM), yet it is of paramount importance in the formation of stars. The densest condensations in molecular clouds are confined to filamentary structures in the Galactic plane; the most striking of these structures are infrared-dark clouds (IRDCs), which reside in the spiral arms where the molecular gas distribution in the Milky Way peaks. IRDCs are thought to be the birthplaces of rich star clusters. Star formation in IRDCs is poorly constrained because light from embedded protostars is heavily obscured by dust. For the first time, Herschel now provides high-resolution access to the far-infrared, where the extinction by dust lessens. This proposal aims to connect the small structures seen by Herschel to large-scale filaments in order to understand the conditions under which IRDCs fragment and ultimately form stars using Herschel, Spitzer, and millimeter (line and continuum) observations of a well-studied sample of IRDCs. We will also conduct a survey of high-resolution molecular line maps using the Plateau de Bure Interferometer and ALMA that will help constrain the kinematics in IRDCs at various stages of their fragmentation. This suite of observations will test predictions of molecular cloud simulations using radiative transfer modeling. By providing powerful observational constraints on models of IRDCs, this project serves as a bedrock for forming a coherent model of the densest phase of the ISM.

分子气体在星际介质（ISM）中的体积分数最小，但它在恒星的形成中至关重要。分子云中的致密凝聚局限于银河平面中的对流结构;这些结构中最引人注目的是红外暗云（IRDC），它位于银河系中分子气体分布峰值的旋臂中。IRDC被认为是丰富的星星集群的诞生地。IRDC中的星星形成受到很大的限制，因为嵌入的原恒星发出的光被尘埃严重遮蔽。这是第一次，赫歇尔现在提供了高分辨率的远红外线，在那里由尘埃消光减少。该提案旨在将Herschel观察到的小结构与大尺度细丝连接起来，以便使用Herschel，Spitzer和毫米（线和连续体）观测充分研究的IRDC样本来了解IRDC碎片并最终形成恒星的条件。我们还将使用Plateau de Bure干涉仪和阿尔马进行高分辨率分子谱线图的调查，这将有助于限制IRDC在其碎片化的各个阶段的运动学。这套观测将测试使用辐射传输模型的分子云模拟预测。通过对IRDC模型提供强有力的观测约束，该项目为形成ISM的denominant阶段的连贯模型奠定了基础。