Making More Realistic Galaxy Clusters: Confronting AMR Cosmological Simulations of Thermal and Nonthermal Processes with Observations

星系团可以用来约束宇宙学参数，如宇宙常数，是暗物质和暗能量的重要探测器。然而，它们在这些作用中的使用受到了它们在诸如宇宙射线和磁场等非线性热和非热过程中剩余的系统不确定性的限制。该项目的重点是使用先进的自适应网格加密(AMR)宇宙磁流体动力学(MHD)N体计算机模拟，并受多波长观测的物理约束。首席调查员利用以前的NSF资金开发了支持这些调查的框架，使用了Enzo计算机代码。在拟议的项目中，一个新的辐射冷却计算机软件模块Cloudy将与三种不同的分布式加热模型相结合-恒星粒子、大质量星系结构和活动星系核。这些对模拟的补充将有助于提供更真实的星系团演化模型，这将改善我们对星系团属性的一般理解，例如当前质量估计中的偏差以及使用星系团作为精密宇宙学探测器的限制。该项目建立在之前NSF资助的开发代码来模拟星系团演化的工作基础上。拟议的更先进的模拟将为解释即将到来的Sunyaev-Zeldovich效应、弱透镜、无线电和X射线调查奠定重要和及时的基础。拟议的工作将极好地将模拟与射电、X射线和伽马射线光谱部分的观测紧密匹配。这项工作处于这类调查的前沿。首席调查员提供了几种扩大该项目影响的方法。在教育方面，(1)一名博士后研究员和一名研究生将参与并接受该项目的指导，(2)模块将被整合到本科生和研究生的课程中，以教授诸如大尺度结构形成和宇宙湍流等物理原理。为了向公众宣传，宇宙学模拟将被纳入当地的公共天文馆计划，并在全国范围内免费分发给其他天文馆。最后，首席调查员将向公众提供开发的软件模块，使整个科学界受益。

Clusters of galaxies can be used to constrain cosmological parameters such as the cosmological constant and are an important probe of dark matter and dark energy. However, their use in these roles is limited by their remaining systematic uncertainties in such nonlinear thermal and nonthermal processes, such as cosmic rays and magnetic fields. This project is focused on using advanced adaptive mesh refinement (AMR) cosmological magnetohydrodynamic (MHD) N-body computer simulations with physics constrained by multiwavelength observations. The principal investigator used previous NSF funding to develop the framework to support these investigations using the Enzo computer code. In the proposed project, Cloudy, a new radiative cooling computer software module, will be combined with three different models for distributed heating---star particles, massive galaxy constructs, and active galactic nuclei. These additions to the simulations will help provide more realistic modeling of cluster evolution that will improve our general understanding of cluster properties, such as biases in current mass estimation and limitations of using clusters as probes of precision cosmology.The project builds on previous NSF-funded work on developing code to simulate cluster evolution. The proposed more advanced simulations will lay important and timely groundwork for interpreting upcoming Sunyaev-Zeldovich Effect, weak lensing, radio, and X-ray surveys. The proposed work will do an excellent job of closely matching simulations with observations in the radio, X-ray, and gamma-ray portions of the spectrum. This work is at the forefront of such investigations.The principal investigator offers several ways to extend the impact of this project. Educationally, (1) a postdoctoral fellow and a graduate student will participate and be mentored in the project, and (2) modules will be integrated into undergraduate and graduate coursework to teach such physical principles as large scale structure formation and turbulence in the Universe. For public outreach, cosmological simulations will be incorporated into public planetarium programs locally and freely distributed nationally to other planetariums. Finally, the principal investigator will make the developed software modules publicly available to the benefit of the entire scientific community.