The Formation and Impact of Nascent Globular Star Clusters

恒星形成是决定我们宇宙性质的最重要的过程之一。恒星的形成以各种方式改变了星系。例如，大质量恒星的密度影响着星系中有多少物质被射入星际空间。大质量恒星的数量决定了可用于形成复杂分子的重元素的丰度，包括那些构成生命基础的分子。对其环境影响最大的恒星形成模式发生在“超级星团”(SSCS)中。这些超级星团将数千颗猛烈的大质量恒星打包成小体积，这些密集的大质量恒星区域在其宿主星系中充当炸弹的角色。在过去的几十年里，我们获得了关于超级星团的丰富知识。例如，现在已经知道，超级星团在宇宙的早期大量形成。我们还知道，古老的超级星团(称为“球状星团”)在今天的宇宙中大量存在。然而，目前还不知道这些星团是如何形成的。也不知道它们的属性如何依赖于它们出生的环境。这个项目将使用阿塔卡马大型毫米/亚毫米阵列(ALMA)和美国国家科学基金会的超大型阵列的新功能来促进我们的知识。利用这些设备的观测将使研究形成超星团的环境成为可能。这位调查员将扩大她的教育和外展项目，名为“黑暗的天空，光明的孩子”。这位研究人员将把该计划扩展到南弗吉尼亚州的农村社区。ALMA的结果为超级星团的起源提供了诱人的线索，包括已知的第一个此类星团的分子先驱的例子。后续观测正在进行中，以在恒星形成之前限制分子云中的物理条件。ALMA对新生的星体干细胞(在恒星形成后)的额外观测揭示了分子谱线强度和比率相对于星系团的演化状态的明显趋势。该计划的主要科学目标包括：(1)确定更多的SSCs分子前体(从一个增加样本大小)，(2)限制形成超级星团所需的物理环境，(3)量化这些极端恒星形成区域的恒星形成效率，以及(4)编码分子谱线强度和比率与星团动力学之间的关系。这些结果将提供模板，帮助解释来自更遥远宇宙中未分辨来源的分子线比率。解决这些问题所需的无线电、毫米和亚毫米波长的观测已经获得，目前正在进行中，并计划在今年提出建议。

Star formation is one of the most important processes in determining the properties of our Universe. The formation of stars changes galaxies in a variety of ways. For example, the density of massive stars affects how much material in a galaxy is blasted into intergalactic space. The number of massive stars determines the abundance of heavy elements available to form complex molecules, including those that are the basis of life. The mode of star formation that has the strongest impact on its environment takes place in "super star clusters" (SSCs). These super star clusters pack thousands of violent massive stars into small volumes, and these dense regions of massive stars act as bombs in their host galaxies. Over the last few decades we have gained a wealth of knowledge about super star clusters. For example, it is now known that super star clusters were formed in large numbers at early times in the Universe. It is also known that ancient super star clusters (called "globular clusters") are present in great numbers in the Universe today. However, it is not yet known how these clusters form. Nor is it known how their properties depend on the environment they are born in. This project will use new capabilities of the Atacama Large Millimeter/submillimeter Array (ALMA) and NSF's Very Large Array to advance our knowledge. Observations with these facilities will enable the investigation of the environments in which super star cluster are formed. The investigator will expand her education and outreach program, called "Dark Skies, Bright Kids." The investigator will extend the program to rural communities in Southern Virginia.Results from ALMA have provided tantalizing clues about the origin of super star clusters, including the first known example of a molecular precursor for such a cluster. Follow-up observations are underway to constrain the physical conditions in the molecular cloud before stars have formed. Additional ALMA observations of nascent SSCs (after the stars have formed) have revealed an apparent trend in molecular line strengths and ratios with respect to the evolutionary state of the cluster. The main scientific goals of this program to be addressed with this program include the following: (1) Identify additional molecular precursors to SSCs (increasing the sample size from one), (2) Constrain the physical environments required to form super star clusters, (3) Quantify the star formation efficiencies of these extreme star-forming regions, and (4) Codify the relationship between molecular line strengths and ratios and cluster dynamics. These results will provide templates to help interpret molecular line ratios from unresolved sources in the more distant universe. The observations at radio, millimeter, and sub-millimeter wavelengths required to address these issues are already obtained, currently underway, and planned for proposals this year.