Magnetic Fields and Carbon Chemistry in Star Forming Regions

这个建议集中在现代天体物理学中两个及时和重要的问题：1）哪些星星和行星形成环境形成生物学上重要的分子，以及什么样的化学物质在不同的区域占主导地位？2)磁场如何影响形成分子云的星星的形状和结构，以及这如何影响随后恒星和行星的形成？为了解决这些问题，我请求资助两个长期研究项目。1)高质量星星形成区（HMSF）中复杂有机分子（COM）与碳链分子（CCM）的研究复杂分子在空间的许多不同环境中被发现。虽然很多注意力都集中在COM的天体生物学重要性上，但CCM在生物学上也很重要，因为即使是简单的环物种，如c-C3 H2，也可能是产生更大生物分子的关键;如碳水化合物。虽然迄今为止大多数研究都集中在少数孤立的低质量核心上，但大多数恒星（包括低质量恒星）都形成于HMSF区域。已知COMs在HMSF地区的热核中丰富。然而，人们认为这些地区的集束弹药不足。因此，在这个项目中，我们将着手进行一项观测活动，以检测和绘制HMSF区域样本中的各种CCM。观测的建模将帮助我们了解时间尺度和物理条件（即密度，紫外线场强，温度等），这些条件在设定HMSF区域观测到的丰度时非常重要，并将其直接与低质量核心的类似观测和理论工作进行比较。2)与形成分子云的星星有关的大尺度磁场的三维形态和强度的研究。 研究表明，磁场在分子云的形成和演化中可能很重要。特别是，有人提出，围绕云的螺旋磁场可以稳定云，防止引力坍缩。然而，这种螺旋场的存在缺乏观测证实。这主要是因为测量云中磁场强度的传统方法存在一些固有的困难。在过去的几年里，我们已经创造了一个新的和新颖的技术来测量视线磁场（Blos）的分子云。使用这种技术，我们发现Blos是围绕云的一致螺旋场，但由于数据的限制，我们不能排除其他几何形状。在这个项目中，我们建议完善我们的技术，并已开始在VLA望远镜上进行一个项目，以更高的灵敏度调查分子云的样本。我们的目标是在分子云中产生高灵敏度，高分辨率的3D磁场几何图形，误差足够小，我们可以自信地确定磁场几何图形。

This proposal focusses on two timely and important questions in modern astrophysics: 1) Which star & planet forming environments form biologically important molecules, and what kinds of chemistries dominate in different regions? 2) How do magnetic fields affect the shape and structure of star forming molecular clouds, and how does this influence the subsequent formation of stars and planets? To address these questions, I request funding to support two long-term research projects. 1) A study of Complex Organic Molecules (COM) vs Carbon Chain Molecules (CCM) in High Mass Star Forming (HMSF) regions Complex molecules have been identified in many different environments in space. While much attention has been given to the astrobiological importance of COMs, CCMs are also biologically important because even simple ring species like c-C3H2 may be key to producing larger biomolecules; such as carbohydrates. While most studies to date have focussed on a few isolated, low mass cores, most stars (including low mass stars) form in HMSF regions. COMs are known to be abundant in hot cores in HMSF regions. CCMs, however, are thought to be deficient in these regions. Therefore, in this project we will embark upon an observational campaign to detect and map a variety of CCMs in a sample of HMSF regions. Modeling of the observations will help us understand the time scales and physical conditions (i.e. density, UV field strength, temperature, etc) that are important in setting the observed abundances in HMSF regions and directly compare this to similar observational and theoretical work for low mass cores. 2) A study of the 3D morphology and strength of large-scale magnetic fields associated with star forming molecular clouds. Studies have shown that magnetic fields can be important in the formation and evolution of molecular clouds. In particular, it has been proposed that a helical magnetic field wrapping around a cloud could stabilize it against gravitational collapse. The existence of such helical fields, however, has lacked observational confirmation. This is mainly because the traditional methods to measure magnetic field strengths in clouds have a number of inherent difficulties. Over the past few years we have created a new and novel technique to measure the line-of-sight magnetic field (Blos) in molecular clouds. Using this technique, we found that Blos was consistent helical fields wrapping around the clouds but, due to limitations in the data, we could not rule out other geometries. In this project we propose to refine our technique and have embarked on a project at the VLA telescope to survey a sample of molecular clouds with greater sensitivity. The goal is to produce highly sensitive, high resolution maps of the 3D magnetic field geometry in molecular clouds with small enough errors that we can confidently determine the magnetic field geometry.