Origin and evolution of cosmic magnetism

宇宙磁力的起源与演化

• 批准号: RGPIN-2019-04848
• 负责人: Stil, Jeroen
• 金额: $ 1.75万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763108
• 关键词: Origin; evolution; cosmic; magnetism

Observations show that magnetic fields are ubiquitous in the cosmos. Together with gravity, cosmic magnetic fields direct the flow of plasma and cosmic rays, and, indirectly, the motion of neutral gas. Still, we cannot answer basic questions about the structure of cosmic magnetic fields, the origin of large-scale magnetic fields in galaxies, and the properties of turbulence in magnetized plasma in space. Our lack of understanding of cosmic magnetic fields leaves major gaps in the physics of galaxy evolution, from the retention of hot gas and cosmic rays in the disk to support of cold molecular clouds against gravitational collapse. Galaxies represent the visible part of structure in the universe. It is here that stellar nucleosynthesis builds elements beyond hydrogen, helium and lithium. After nearly 14 billion years of evolution, all observable gas appears enriched by the products of stellar nucleosynthesis, even in intergalactic space. This fact bears testimony to the impact that the life cycle of stars on a galactic scale has on the evolution of galaxies and their wide environment. Some galaxies also host active galactic nuclei (AGN), that are powered by accretion of matter on a central, supermassive black hole. Beams of matter called jets are ejected at bulk relativistic speed, and form giant magnetic radio lobes in intergalactic space much larger than a galaxy. The ejection of matter, and its its associated kinetic energy and momentum, by stars and AGN is referred to as stellar feedback and AGN feedback. We cannot understand galaxy evolution without the physics of feedback. Magnetic fields play an important role in the physics of feedback, for example during various stages of star formation, acceleration and diffusion of cosmic rays, constraining galactic outflows, and collimating jets. In turn, stellar feedback provides energy for dynamo effects that amplify magnetic fields, while outflows and jets from AGN can inject magnetic fields into the intergalactic medium. Observations that reveal the structure an dynamical importance of magnetic fields provide crucial guidance for models of feedback and turbulence. This research program targets the complex feedback processes between gas and magnetic fields in galaxies, and their relation to the emergence of cosmic magnetic fields. In the next five years, we will lead by combining measurements of the velocity of plasma and neutral gas in the local interstellar medium with measurements of the magnetic field from the energy injection scale to the smallest observable turbulence. We will address the question of how magnetic fields evolved over cosmic time in spiral galaxies and in the lobes of radio galaxies - the main sites for stellar and AGN feedback. My group excels in stacking, integrated polarization of galaxies, and statistics of rotation measures. We will lead application of these techniques toward our objectives through defined science projects proposed according to survey policies.

观察结果表明，磁场在宇宙中无处不在。与重力一起，宇宙磁场引导血浆和宇宙射线的流动，并间接地引导中性气体的运动。尽管如此，我们仍无法回答有关宇宙磁场结构，星系中大规模磁场的起源以及空间中磁等离子体中湍流的特性。我们对宇宙磁场的了解不足，从热气和宇宙射线的保留到磁盘中的保留到支持冷分子云防止重力崩溃的情况下，留下了主要差距。星系代表了宇宙中结构的可见部分。正是在这里，恒星的核共生产生了氢，氦和锂之外的元素。经过将近140亿年的进化，即使在白术空间中，所有可观察的气体似乎都被恒星核骨的产物富含。这一事实证明了恒星对银河系及其广泛环境的演变的影响。一些星系还容纳了主动银河核（AGN），这些核（AGN）是由中央超级黑洞上物质积聚的。称为喷气机的物质横梁以批量的相对速度弹出，并形成巨大的磁性无线电爱在与银河系大得多的绘制空间中。恒星和AGN的物质弹出及其相关的动能和动量被称为恒星反馈和AGN反馈。没有反馈物理学，我们将无法理解星系的演变。磁场在反馈物理学中起着重要作用，例如在恒星形成的各个阶段，宇宙射线的加速和扩散，限制银河出口和准确的喷气机。反过来，恒星反馈为放大磁性的发电机效应提供了能量。田地，而来自AGN的插座和喷气机可以将磁场注入磁场间介质。揭示结构磁场的动态重要性的观测值为反馈和湍流模型提供了至关重要的指导。该研究计划针对星系中气体和磁场之间的复杂反馈过程，以及它们与宇宙磁场的出现的关系。在接下来的五年中，我们将通过结合局部星际介质中血浆和中性气体速度的测量以及从能量注入量表到最小可观察的湍流的测量。我们将解决磁场如何在螺旋星系中以及对射电星系的热爱中如何发展的问题 - 恒星和AGN反馈的主要地点。我的小组在堆叠，星系的综合极化和旋转测量统计方面表现出色。我们将通过根据调查政策提出的定义的科学项目来领导这些技术将这些技术应用于我们的目标。