Parkes observations for project P996 semester 2019OCTS_06

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.

我们提出将利用超宽带低（Ultra-Wideband Low, UWL）接收机，对距离大于5千秒差距（kpc）的遥远南天脉冲星开展偏振测量，以研究遥远旋臂内部及旋臂间的银盘磁场结构。过往帕克斯（Parkes）脉冲星观测已在邻近旋臂及臂间区域中发现了磁场反转现象。我们期望借助UWL接收机更高的灵敏度，将此类研究拓展至更远的区域，从而能够更清晰地甄别银盘磁场结构的不同理论模型。鉴于基于色散量（DM）的脉冲星距离存在固有不确定性，需对多组脉冲星的数据取平均，才能确切验证任何磁场反转现象。本研究将对银河磁场生成理论，以及诸如宇宙射线物理学这类需要依托大尺度银河磁场知识开展理论诠释的研究领域，产生重要的科学意义。