Radio Polarimetry: A New Window on the Magnetic Universe

20世纪天文学家的一个重大发现是，恒星、行星、星系，甚至弥散的星际气体，都具有磁性。这些宇宙磁场在控制恒星和星系的形成、老化和演化过程中起着至关重要的作用。此外，这种自然产生的磁性调节太阳活动和空间天气，保护地球免受有害粒子的侵害，对鸟类和其他物种的导航至关重要。****然而，尽管天体物理磁体的重要性和无处不在，我们不知道是什么创造了它们，也不知道它们是如何在数十亿年的宇宙时间里保持强度的。不幸的是，即使是最大的望远镜也看不见磁场。****有了现代射电望远镜，我们终于可以打开这个磁性宇宙的窗口。在这个项目中，我将使用一种叫做“法拉第旋转”的效果，在这种效果中，来自背景物体的射电光线在穿过具有显著磁性的气体云时发生了微妙的变化。通过测量来自数百万遥远微弱星系的射电辐射中的法拉第旋转，我的目标是探测整个宇宙的磁场。由此产生的星际气体、遥远星系和星系间空间的三维磁性图将揭示宇宙磁性的样子、它们来自哪里，以及它们在不断演变的宇宙中扮演了什么角色。****另一个重要的目标是测试平方公里阵列所需的技术和技术，这是一个数十亿美元的项目，有望为加拿大带来巨大的科学、工程和经济机会。通过培养下一代射电天文学家，我的目标是培养一批关键的毕业生，他们不仅是杰出的科学家，而且对潜在的仪器和技术问题有深刻的理解。通过他们在天体物理学、仪器和软件开发方面的独特专业知识，这些研究人员将准备好领导平方公里阵列上的重大科学项目，并因此回答物理学和天体物理学的基本问题

One of the many remarkable discoveries made by 20th century astronomers was that stars, planets, galaxies, and even diffuse interstellar gas, are all magnetic. These cosmic magnetic fields play a vital role in controlling how stars and galaxies form, age and evolve. In addition, this naturally occurring magnetism regulates solar activity and space weather, protects the Earth from harmful particles, and is vital for the navigation of birds and other species.****However, in spite of the importance and ubiquity of astrophysical magnets, we do not understand what creates them, or how they maintain their strength over billions of years of cosmic time. And unfortunately, magnetic fields are invisible even to the largest telescopes.****With modern radio telescopes, we can finally open the window to this magnetic Universe. In this project, I will use an effect called "Faraday rotation", in which radio light from a background object is subtly changed when it passes through a cloud of gas in which significant magnetism is present. By measuring Faraday rotation in the radio emission from millions of faint, distant, galaxies, I aim to detect magnetic fields throughout the cosmos. The resulting three-dimensional maps of magnetism in interstellar gas, in distant galaxies and in intergalactic space will reveal what cosmic magnetics look like, where they have came from, and what role they have played in the evolving Universe.****An additional important goal is to test the techniques and technology needed for the Square Kilometre Array, a multi-billion dollar project that promises enormous scientific, engineering and economic opportunities for Canada. By training the next generation of radio astronomers, I aim to develop a critical mass of graduates who are not only outstanding scientists, but who have a deep understanding of the underlying instrumental and technical issues. Through their unique expertise across astrophysics, instrumentation and software development, these researchers will be ready to lead the major scientific programs on the Square Kilometre Array, and to thus answer fundamental questions in physics and astrophysics.**