Cosmological evolution of large-scale magnetic fields in galaxies and the intergalactic medium

磁场结构只在附近的盘星系中得到了很好的研究，而它们的演化却由于现今射电望远镜的灵敏度有限而未被探索。未来射电望远镜在低通量密度下观测到的主要来源是形成恒星的盘状星系，例如SKA，将在z ~ 3左右被探测到。因此，可以通过来自遥远盘星系的总同步辐射和偏振射电辐射的演化来研究磁场结构的演化。通过法拉第旋转测量介于中间的盘状星系对偏振背景类星体的影响甚至更大，这将使磁场的演化可以追踪到更高的红移，SKA的z ~ 5。在这个项目中，我们的目标是（i）开发银河系和星系间磁场的演化模型，（ii）开发工具，使用SKA及其探路者未来无线电调查的数据来调查磁场的演化，以及（iii）用现有的深层无线电调查来测试这些工具。更好地了解年轻星系的磁性历史可能有助于解决星系形成和演化的基本宇宙学问题。

The magnetic field structure has been well studied only for nearby disk galaxies while their evolution is unexplored because of the limited sensitivity of present-day radio telescopes. The dominant population of sources at low flux densities observable with future radio telescopes is the population of star-forming disk galaxies which, e.g. with the SKA, would be detected up to about z ~ 3. Hence, the evolution of magnetic field structures can be studied by means of the evolution of total synchrotron and polarized radio emission from distant disk galaxies. Faraday rotation measurements of intervening disk galaxies towards polarized background quasars are even more powerful and will allow the evolution of magnetic fields to be traced to even higher redshifts, z ~ 5 with the SKA. In this project we aim (i) to develop evolutionary models for galactic and intergalactic magnetic fields, (ii) to develop tools for investigating the evolution of magnetic fields using the data from future radio surveys with the SKA and its pathfinders, and (iii) to test these tools with existing deep radio surveys. A better understanding of the history of magnetism in young galaxies may help to solve fundamental cosmological questions on the formation and evolution of galaxies.