Formation of Galactic Massive Stars and Star Clusters

这项工作建立在Bolocam银河平面调查（BGPS）的基础上，首席研究员先前得到了NSF的支持。现在，在该调查中发现的最大质量的原星团块被先进的观测设备以尽可能高的角分辨率从近红外到厘米波长进行研究这些观测用于了解大质量恒星和星团如何在银河系以及其他星系中形成。了解大质量恒星的形成是完整了解星系结构和演化的必要组成部分。关于大质量恒星的知识在天文学的其他领域也很重要，例如，这些恒星通过核合成产生重元素，它们在活动星系核的生长中发挥作用。大质量星星的形成有两种主要的机制：相互作用的团簇的竞争性吸积和大质量核心在高压环境中的孤立坍塌。在这项工作中，它是解决如果大质量的恒星形式作为孤立的系统，或者如果他们与兄弟星相互作用，并竞争从他们的父集团吸积。这项工作也导致更好地了解反馈的作用，如外流和紫外线辐射对随后的星星形成的团块。这项工作解决的其他问题是什么决定了形成的恒星数量和恒星质量上限，以及什么条件导致了非束缚的OB协会与引力束缚的星团。观测目标是银河系最大质量的恒星形成区域的高空间分辨率，将使用Apache Point Observatory（APO），扩展的超大阵列（EVLA），毫米波天文学研究组合阵列（CARMA）、阿塔卡马大型毫米波阵列（阿尔马）和双子座等望远镜上的自适应光学系统。大量的数据已经可以获得，该计划的一个重要部分是用最先进的仪器和望远镜进行新的观测。其中一些工具是在国家科学基金的资助下开发的。目标清单包括两个最近的活跃高光度源，猎户座A和仙王座A，其中几种观测方法已经得到验证，并发现了重要的动力学相互作用的证据。该项目涉及一个大型研究团队，加强了学术网络基础设施。两名研究生在他们的博士论文工作作为这个项目的一部分，并有更多的研究生和本科生参与的机会。研究生也将积极参与外展活动。作为这项工作的一部分，首席研究员在博尔德的Sommer-Bausch天文台（SBO）实施了一项本科生研究计划。这向来自科罗拉多大学的物理学和天文学本科生介绍了在最近的恒星形成区域中对年轻恒星的光度监测，这些区域足够清晰，可以用24”SBO望远镜在可见波长进行观测。 令人惊叹的图像预计将从这个项目中找到在菲斯克天文馆和丹佛自然科学博物馆的流行讲座中使用，并将通过互联网和菲斯克天文馆传播。

This work builds upon the Bolocam Galactic Plane Survey (BGPS) for which the principal investigator had previous support from the NSF. Now the most massive proto-cluster clumps found in that survey are investigated with advanced observational facilities at the highest possible angular resolution from near-infrared through cm-wavelengths These observations are used to learn how massive stars and clusters form in the Milky Way as well as in other galaxies. Understanding the formation of massive stars is a necessary piece in a complete picture of galactic structure and evolution. The knowledge about massive stars is also important in other areas of astronomy, e.g., these stars produce heavy elements through nucleosynthesis, and they play a role in the growth of Active Galactic Nuclei. Two major mechanisms have been proposed for massive star formation: Competitive accretion from a cluster of interacting clumps and isolated collapse of massive cores in a high pressure environment. In this work it is addressed if massive stars form as isolated systems, or if they interact with sibling stars and compete to accrete from their parent clump. This work also leads to a better understanding of the role of feedback such as outflows and UV radiation on subsequent star formation in the clump. Other questions addressed by this work are what determines the number of stars formed and the upper stellar mass-limit, and what conditions lead to unbound OB associations versus gravitationally bound clusters.The observations target the Galaxy's most massive star-forming regions at high spatial resolution and will use the Apache Point Observatory (APO), the Expanded Very Large Array (EVLA), the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), the Atacama Large Millimeter Array (ALMA) and adaptive optics on telescopes such as Gemini. A large amount of data is already available and a significant part of the program is for new observations with the most advanced instruments and telescopes. Several of these instruments have been developed with funding from the NSF. The target list includes the two nearest active, high-luminosity sources, Orion A and Cepheus A, where several of the observing methods have been demonstrated and evidence of significant dynamical interactions has been discovered.This project involves a large team of researchers which strengthens the academic network infrastructure. Two graduate students work on their doctoral theses as part of this project, and there are opportunities for more graduate- and undergraduate student participation. The graduate students will also be actively involved in the outreach activities.A s part of this work the principal investigator implements an undergraduate research program at Sommer-Bausch Observatory (SBO) in Boulder. This introduces physics and astronomy undergraduate students from the University of Colorado to photometric monitoring of young stars in the closest star-forming regions that are sufficiently un-obscured to permit observations at visual wavelengths with the 24" SBO telescope. Stunning images are expected from this project which find use in popular talks at Fiske Planetarium and the Denver Museum of Nature and Science, and which are to be disseminated via the internet and Fiske planetarium.