Cosmic magnetism

磁性是自然界的基本力量之一。 已知磁场存在于星系中，从容纳超大质量黑洞的高能核到圆盘中恒星之间的扩散介质。 众所周知，磁力在控制许多驱动星系演化的现象中至关重要，从星星形成，结构形成，大尺度动力学，以及高能粒子的限制和加速。尽管它们在宇宙中无处不在和重要性，但人们对宇宙磁场的起源和演化知之甚少。 射电辐射的偏振是宇宙磁场探测的关键之一。 宇宙磁已被确定为目前正在建造或计划建造的下一代国际射电天文学设施的关键科学目标之一，如EVLA，澳大利亚SKA Pathfinder和SKA。本提案中所述的研究将通过使用世界上最强大的射电望远镜开展大型观测项目，绘制天空在空间和频率上的偏振发射图，大大促进我们对宇宙磁场的起源、演变和作用的理解。 GALFACTS使用阿雷西博望远镜上的多路馈电喇叭阵列对40%的天空进行成像，其灵敏度是以前任何偏振调查的五倍，并具有频率依赖的完整光谱信息。 该项目将测量100，000多个射电源的偏振特性，并绘制磁场与银河系星际介质相互作用产生的扩散偏振辐射图。 EVLA深偏振场将测量来自星系盘的微弱偏振信号，直到高红移，追踪宇宙年龄的一个重要部分的星系场的演变。 这些项目结合了联合收割机先进的观测和数据处理技术的开发、尖端科学、与全球领先研究人员网络的合作，以及与主要天文台和工业界的伙伴关系-培养能够在先进技术和世界级科学的界面上工作的年轻科学家。

Magnetism is one of the fundamental forces of nature. Magnetic fields are known to exist in galaxies, from the energetic nuclei that harbour super massive black holes, to the diffuse medium between the stars in the disks. Magnetic forces are known to be critically important in governing many of the phenomena that drive the evolution of galaxies, from star formation, structure formation, large-scale dynamics, and confinement and acceleration of high-energy particles. Despite their ubiquity and importance in the Universe, very little is known about the origin and evolution of cosmic magnetism. Polarization of radio emission is one of the key probes of cosmic magnetic fields. Cosmic magnetism has been identified as one of the key science goals of next generational international radio astronomy facilities that are currently under construction or planned, such as the EVLA, the Australia SKA Pathfinder and the SKA. The research described in this proposal will significantly advance our understanding of the origin, evolution and role of cosmic magnetic fields by using the world's most powerful radio telescopes to carry out large observing projects that map the polarized emission from the sky in both space and frequency. GALFACTS uses the multiple-feed horn array on the Arecibo telescope to image 40% of the sky to sensitivity five times deeper than the any previous polarization survey and with full spectral information of frequency dependence. This project will measure the polarization properties of over 1,00,000 radio sources and map the diffuse polarized emission from the interaction of magnetic fields with the interstellar medium in our Galaxy. The EVLA Deep Polarization Field will measure the faint polarized signals from disks of galaxies out to high redshifts, tracing the evolution of fields in galaxies over a significant fraction of the age of the universes. These projects combine development of advanced techniques for observing and data processing, cutting edge science, collaborations with a global network of leading researchers, and partnership with major observatories and industry - fertile environment to train young scientists who can work at the interface of advanced technologies and world-class science.