Regulating star formation in diverse galactic environments

调节不同星系环境中的恒星形成

• 批准号: RGPIN-2014-06661
• 负责人: Wilson, Christine
• 金额: $ 3.79万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=668669
• 关键词: Regulating; star; formation; diverse; galactic

In our own Milky Way and in other galaxies, stars form inside dense clouds of molecular hydrogen gas. How galaxies form and evolve with time is intimately tied to this process of star formation. However, the effect of the larger scale environment on the molecular gas content of galaxies is poorly understood. I will measure the molecular gas content and properties in a sample of nearby spiral galaxies probing environments from isolated galaxies to galaxy groups to the massive Virgo cluster of galaxies. One possibility is that gravitational interactions with neighbouring galaxies are responsible for driving the conversion of atomic hydrogen gas to molecular hydrogen gas through radial inflows. This unique work will determine the role of environment in shaping the molecular gas content of galaxies and place this work in the context of models of galactic star formation and galaxy evolution. **The violent mergers of two galaxies produce some of the most extreme star formation environments in the local universe, with stars forming at a rate that is ten to one hundred times faster than in normal galaxies. I will measure how the physical and dynamical properties of the molecular gas change during the merger process to pinpoint the mechanisms responsible for the increase in the rate of star formation in galaxy mergers as well as the similar increase in the rate of gas consumption. I will also measure the rate of cooling in the molecular gas and use radiative transfer models to constrain the heating sources for the gas, such as ultraviolet photons, X-ray photons, or shocks. My work will provide a critical test of the input physics to numerical models of galaxy mergers, as well as models of galaxy formation in the early universe. **One of the most important issues in astrophysics today is understanding what sets the distribution of masses with which stars are born. I will complement my work on extragalactic star formation with a detailed study of the properties of dense cores in molecular clouds in our own Milky Way. These dense cores are known to be the sites where individual stars are formed. I will measure the distribution of masses of the cores and determine whether the properties of the cores change with the local environment, from isolated cores to cores along filaments to small clusters of cores. I will also determine whether filaments provide the necessary environment for the formation of dense cores. My work will test the robustness of our understanding of the relationship between the dense cores and the distribution of masses with which stars are born.

在我们自己的银河系和其他星系中，恒星在分子氢气的致密云中形成。星系如何随着时间的变化形成和演变与这种恒星形成过程密切相关。但是，较大规模环境对星系分子气体含量的影响知之甚少。我将在附近螺旋星系样品中测量分子气体含量和性能，从孤立的星系到星系基团再到大型的处女座星系群。一种可能性是，与邻近星系的重力相互作用负责通过径向流入将原子氢气转化为分子氢气。这项独特的工作将确定环境在塑造星系的分子气体含量中的作用，并将这项工作放在银河恒星形成和星系进化模型的背景下。 **两个星系的暴力合并产生了当地宇宙中一些最极端的恒星形成环境，恒星的形成速度比正常星系快十到一百倍。我将在合并过程中衡量分子气体变化的物理和动力学特性，以查明导致星系合并中星形成速率增加的机制，以及相似的气体消耗速率。我还将测量分子气中的冷却速率，并使用辐射转移模型来限制气体的加热来源，例如紫外光子，X射线光子或冲击。我的工作将为星系合并的数值模型以及早期宇宙中星系形成的模型提供对输入物理的批判性测试。 **当今天体物理学中最重要的问题之一是了解是什么使恒星诞生的群众分布。我将通过对分子云中密集的岩心在我们自己的银河系中的特性进行详细研究，以详细的研究来补充我对外层状恒星形成的工作。这些致密的岩心是形成单个恒星的位置。我将测量核心的质量分布，并确定岩心的性质是否随局部环境的变化，从沿细丝到岩心到小核心簇。我还将确定细丝是否为形成密集的核心提供必要的环境。我的工作将测试我们对密集核心之间关系与恒星诞生的群体分布之间关系的理解的鲁棒性。