Parkes observations for project P996 semester 2019OCTS_03

We propose to measure the polarisation of distant southern pulsars (distance>5kpc) \r\nusing the Ultra-Wideband Low (UWL) receiver to investigate the structure of the Galactic \r\ndisk magnetic field in and between distant spiral arms. Previous Parkes pulsar observations \r\nhave revealed field reversals in nearby arm and interarm regions. We wish to exploit the \r\ngreater sensitivity of the UWL receiver to extend this to more distant regions, thereby allowing \r\nus to distinguish more clearly between different models for the structure of the disk field. \r\nBecause of the intrinsic uncertainty in DM-based pulsar distances, averaging data over groups \r\nof pulsars is necessary to confidently demonstrate any magnetic-field reversals.\r\nThis work will have important implications for theories for the generation of Galactic magnetic \r\nfields and for other areas, e.g., cosmic-ray physics, which depend on a knowledge of the \r\nlarge-scale Galactic magnetic field for their interpretation.

我们提出利用超宽带低（Ultra-Wideband Low, UWL）接收机，对距离大于5千秒差距的南天遥远脉冲星开展偏振测量，以探究遥远旋臂内部及旋臂之间的银盘磁场结构。此前帕克斯（Parkes）开展的脉冲星观测已在邻近旋臂及臂间区域发现了磁场反转现象。我们期望借助UWL接收机的更高灵敏度，将此类研究拓展至更遥远的天体区域，从而能够更清晰地甄别不同的银盘磁场结构模型。由于基于色散量（Dispersion Measure, DM）的脉冲星距离测量存在固有不确定性，需对多组脉冲星的观测数据进行平均处理，方能可靠地验证任何磁场反转现象。本研究对于银河系磁场生成理论，以及其他依赖大尺度银盘磁场知识开展物理解释的研究领域（如宇宙线物理学）均具有重要意义。