Elliptical Polarization as a Probe of the Magnetic Fields in AGNs

活动星系核(AGN)中心的黑洞和吸积盘，以及在这些源中常见的、显然来自中央引擎的射电喷流之间的联系，仍然是一个悬而未决的问题。过去的工作已经成功地将射电喷流视为具有被动磁场的流体力学流动，即使磁能必须很高。这项研究将探索这些制度之间的联系，利用多频射电偏振观测直接测量磁场强度和方向。在几周到几十年的时间尺度上，对多个频率的线性和圆极化进行单碟式和干涉式观测都是必要的，将获得这些观测结果，并使用相关的模型进行解释。一个有价值的副产品将是关于粒子组成和粒子能量分布的信息，这些信息是尚不清楚的基本喷流特性。独特的测量数据库将随时可用，这项研究将有助于维护美国为数不多的用于学生实践培训的射电望远镜之一。*

AST-0307629AllerThe link between the black hole and accretion disk at the heart of active galactic nuclei (AGN), and the radio jets commonly observed in these sources and apparently emanating from the central engine, remains an unanswered question. Past work has successfully treated the radio jets as hydrodynamical flows with passive magnetic fields, even though the magnetic energy must be high. This research will explore the connection between these regimes, using multi-frequency radio polarimetry observations to measure directly the magnetic field strength and orientation. Both single dish and interferometric observations of linear and circular polarization at multiple frequencies, over timescales of weeks to decades, are necessary and will be obtained, and interpreted using associated modeling. A valuable by-product will be information on particle composition and particle energy distribution, fundamental jet properties which remain unknown. The database of unique measurements will be made readily available, and the research will help maintain one of the few radio telescopes available in the US for hands-on student training.***