AGNs to the IGM: Tracing the Energy Flow Through Radio Galaxies

这个建议是使用x射线观测约束下的理论三维MHD模型和低频射电成像来研究射电星系喷流和叶中的能量沉积和扩散。目标是将磁场和宇宙射线与喷流动力学和射电星系演化联系起来。这项提议的工作旨在为理解起源于某些星系中心核心的巨大能量现象与这些星系周围巨大的气体环境之间的相互作用提供基本的见解。炽热等离子体的高能流似乎以接近光速的速度从星系核心喷出。当这些流进入星系周围的弥漫等离子体时，相互作用的区域产生相对论性电子并被照亮。这些结构被称为射电星系，它们不仅发射无线电波长的辐射，还发射光学和x射线区域的辐射。这是第一次，新的观测能力将使我们能够直接比较由相同电子群产生的无线电和x射线发射。无线电发射是相互作用区域中弥漫的弱磁场的结果，而特征x射线是宇宙微波背景中电子和光子之间碰撞的结果。同时测量两者是必要的，以确定磁场的强度和电子居群的性质。反过来，这些信息对于推断导致无线电结构的动力学事件的努力是至关重要的输入。研究人员正准备对这些天体进行高度复杂的数值模拟，研究等离子体流动的能量学与从地球上可以观察到的发射之间的关系。在这些研究之后，将对这些巨大的动力结构的演化进行更广泛的探索，以便更好地理解射电星系对填充星系团的气体介质的特性做出贡献的方式。这个话题目前在宇宙结构形成的研究中引起了广泛的兴趣。本项目由美国国家科学基金会星系外天文学和宇宙学项目（AST/EXC）提供资金。****

JonesAST-0071167This proposal is to use both theoretical 3-D MHD modeling constrained by X-ray observations and low-frequency radio imaging to study the deposition and diffusion of energy in the jets and lobes of radio galaxies. The goal is to relate the magnetic field and cosmic rays to the jet dynamics and radio-galaxy evolution.The proposed work aims to add fundamental insights to the understanding of interactions between the enormously energetic phenomena originating in the central cores of some galaxies and the vast, gaseous environments around those galaxies. Energetic streams of hot plasma appear to be expelled from the galactic cores at speeds approaching the speed of light. When those streams plow into the diffuse plasma surrounding the galaxy the interacting regions produce relativistic electrons and become illuminated. Those structures are known as Radio Galaxies and they not only emit radiation at radio wavelengths but also in the optical and x-ray regions. For the first time, new observational capabilities will enable us to directly compare radio and X-ray emissions produced by the same electron populations. The radio emissions are a consequence of weak magnetic fields pervading the interaction regions, while the signature X-rays result from collisions between those electrons and photons in the Cosmic Microwave Background. Simultaneous measurements of both is necessary to find measures of the strengths of the magnetic fields and the properties of the electron populations. That information, in turn is crucial input into efforts to infer the dynamical events leading to the radio structures. The investigators are in position to carry out highly sophisticated numerical simulations of these objects, studying both the relationships between the energetics of the plasma flows and the emissions that can be observed from earth. Those studies will be followed by more general exploration of the evolution of these vast dynamical structures, so as to understand better the ways in which radio galaxies contribute to the properties of the gaseous media that fill clusters of galaxies. That topic is currently of broad interest in the study of cosmic structure formation.Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC).****