Collaborative Research: Exploring the impact of cosmic ray feedback on galaxy evolution

天文学家试图了解星系是如何形成和演化的。大量的物质在引力作用下凝聚成星系。然而，内部的未知力量以星系风的形式排出气体。Ruszkowski和他的合作者试图了解这种缺失的力是否可以由宇宙射线提供。通过计算机模拟，他们将研究宇宙射线对星系风的影响。他们将确定宇宙射线对这些风是否有足够的力量将物质从星系中完全驱逐出去。最终了解星系风的动力将有助于重大进展。这项研究可能会使我们对星系如何演化的理解有质的飞跃。这些模拟的结果将用于令人惊叹的天文馆动画。这样的可视化能吸引公众，激励年轻人学习科学。这项研究将探索一系列的空间尺度。它将包括宇宙射线在孤立的超新星残骸周围传播到星系盘，最后到宇宙星系形成的混合动力学模拟。宇宙射线传输物理将从第一性原理进行模拟。星际介质的局部斑块将使用自适应网格细化进行模拟。这些结果反过来将用于开发用于星系和宇宙形成模拟的子网格模型。这个项目将构成第一个大规模的星系形成研究，包括宇宙射线在所有空间尺度上的传输过程。它将对宇宙射线驱动的星系风的特性做出具体的预测。

Astronomers seek to understand how galaxies formed and evolve. Vast filaments of matter coalesce into galaxies under gravity. However, unknown forces from within expel gas in the form of galactic winds. Ruszkowski and collaborators seek to understand whether this missing force could be provided by cosmic rays. Using computer simulations, they will study effects of cosmic rays on galactic winds. They will determine whether cosmic rays contribute sufficient force to these winds to expel matter from galaxies completely. Finally understanding what powers galactic winds will contribute a major advance. This study may enable a qualitative leap in our understanding of how galaxies evolve. Results of these simulations will be used in stunning planetarium animations. Such visualizations engage the public and inspire young people to study science.This study will probe a range of spatial scales. It will include hybrid kinetic simulations of cosmic ray propagation around isolated supernova remnants out to galactic disks and finally to cosmological galaxy formation. Cosmic-ray transport physics will be simulated from first principles. Local patches of the interstellar medium will be simulated using adaptive mesh refinement. These results in turn will be used to develop sub-grid models for galaxy and cosmological formation simulations. This project will constitute the first large-scale study of galaxy formation to include cosmic-ray transport processes on all spatial scales. It will yield specific predictions for the properties of cosmic-ray driven galactic winds.