Collaborative Research: Toward an Integrative Understanding of Galaxy Clusters: AMR MHD/N-body Simulations of Thermal and Nonthermal Processes

星系团是宇宙中最大的引力束缚结构，因此是强有力的宇宙探测器。也许令人惊讶的是，它们的重子（和可观测的）物质主要存在于星系之间的热的、弥漫的等离子体中，即星团内介质中，而不是像恒星那样的发光物质中。这种簇内介质由热和非热组分组成。热气体在中心区域经历冷却和加热（通过超新星和活动星系核的反馈）。非热成分包括宇宙射线，由冲击和活动星系核产生，以及磁场。尽管它们很重要，但非热成分得到的研究相对较少，部分原因是需要遵循相关物理的数值模拟的挑战。为了缩小我们对星系团环境理解的差距，伯恩斯博士和合作者将应用他们最近开发的自适应网格细化磁流体动力学n体代码来解决这个问题。最值得注意的是，这个新工具能够在大尺度的宇宙环境中进化宇宙射线和磁场。在这里，它将被用来模拟星系团内的热过程和非热过程。这些模拟将反复进行，直到热物理和非热物理的结合能够最好地再现现有的观测结果。通过积极参与这项工作的各个方面，培养博士后和研究生。来自这些模拟的数据和将输出转换为标准观测格式的工具将通过在线档案提供给天文学和更广泛的社区。Burns博士和合作者还将通过他们的数值模拟为从入门天文学到研究生天体物理学的课程构建课程模块，展示宇宙气体和n体粒子动力学的概念。这些可视化也将发展成新的天文馆展示。

Galaxy clusters are the largest gravitationally bound structures in the universe and, therefore, are potent cosmological probes. Perhaps surprisingly, their baryonic (and observable) matter is principally in the hot, diffuse plasma located between the galaxies, i.e., the intracluster medium, not in luminous matter like stars. This intracluster medium is composed of thermal and nonthermal components. The thermal gas undergoes both cooling and heating (via feedback from supernovae and active galactic nuclei) in the central regions. The nonthermal component consists of cosmic rays, generated via shocks and active galactic nuclei, and magnetic fields.Despite their importance, the nonthermal constituents have received relatively little study in part because of the challenges in the numerical modeling needed to follow the relevant physics. In an effort to begin to close this gap in our understanding of galaxy cluster environments, Dr. Burns and collaborators will apply their recently developed adaptive mesh refinement magnetohydrodynamic N-body code to the problem. Most notably, this new tool is capable of evolving both cosmic rays and magnetic fields in the large-scale cosmological environment. Here it will be employed to simulate both thermal and nonthermal processes within galaxy clusters. These simulations will iterated upon until convergence is achieved with a combination of thermal and nonthermal physics that best reproduces available observations. Postdoctoral fellows and graduate students will be trained through active participation in all aspects of this work. The data from these simulations and the tools for converting the outputs into standard observational formats will be made available to the astronomical and broader community through an on-line archive. Dr. Burns and collaborators will also construct course modules showing concepts of cosmological gas and N-body particle dynamics via their numerical simulations for classes ranging from introductory astronomy to graduate astrophysics. These visualizations will also be developed into new planetarium shows.