A Study of Magnetic Fields in the Formation of Molecular Clouds and Stars

恒星是由巨大的氢云形成的，但坍缩的细节仍不清楚。 研究人员将使用计算机模型来模拟云塌缩形成恒星的过程。 研究者试图回答有关星星形成的三个重要问题。 (1)有多少云可以变成星星？ (2)这发生得有多快？ (3)磁场是气体坍缩的最重要的力吗？ 研究人员将进行一系列综合观测，以寻找坍缩气体的第一个特征。星星的形成需要数百万年。天文学家对银河系中许多云的观测是星星形成历史的快照。 计算机模型使天文学家能够将所有这些观测结果组织成一个关于恒星诞生的单一故事。研究人员将制作一系列合成的全星系分子和热气体地图。数值模型使用自适应网格细化，并包括磁场的影响，辐射反馈和云的化学成分模型。 开放源代码ENZO将用于模拟。 模拟的物理尺度为1000 pc，分辨率为100天文单位。 研究人员将从类似于分层银盘中所见的初始条件开始。 在更高的线性分辨率下，模拟将集中在分子云和孕育年轻恒星的致密核心上。将产生力和观测信号的完整组合历史。

Stars form out of giant clouds of hydrogen, but the details of the collapse are still unclear. The investigators will use computer models to simulate the collapses of clouds to form stars. The investigator seeks to answer three important questions concerning star formation. (1) How much of a cloud turns into stars? (2) How fast does this happen? (3) Are magnetic fields the most important force on collapsing gas? The investigator will produce a series of synthetic observations to hunt for the very first signature of collapsing gas. Star formation of takes millions of years. Astronomer's observations of many clouds in our galaxy are snap shots of the history of star formation. The computer models allow astronomers to organize all these observations into a single story of the birth of stars.The investigator will produce a sequence of synthetic, all-galaxy, maps of molecules and hot gas in our galaxy. The numerical models use adaptive mesh refinement and include the effects of magnetic fields, radiation feedback, and models for the chemical composition of the clouds. The open source code ENZO will be used for the simulations. The simulations have a physical scale of 1000 pc and resolution of 100 astronomical units. The investigator will start with initial conditions similar to those seen in the stratified galactic disk. At higher linear resolution, the simulation will be concentrated on molecular clouds and the dense cores that harbor young stars. The complete assembly history of forces and observational signatures will be produced.