Parkes observations for project P996 semester 2019APRS_02

We propose to measure the polarisation of 107 southern pulsars (distance>5kpc. 77 in this semester) using the Ultra-Wideband Low (UWL) receiver to investigate the structure of the Galactic disk magnetic field in and between distant spiral arms. Previous Parkes pulsar observations have revealed field reversals in nearby arm and interarm regions. We wish to exploit the greater sensitivity of the UWL receive r to extend this to more distant regions, thereby allowing us to distinguish more clearly between different models for the structure of the disk field. Because of the intrinsic uncertainty in DM-based pulsar distances, averaging data over groups of pulsars is necessary to confidently demonstrate any magnetic-field reversals. This work will have important implications for theories for the generation of Galactic magnetic fields and for other areas, e.g., cosmic-ray physics, which depend on a knowledge of the large-scale Galactic magnetic field for their interpretation.

我们提出利用超宽带低（UWL）接收器测量107颗南天脉冲星（距离＞5千秒差距，本学期观测77颗）的偏振特性，以研究遥远旋臂内部及旋臂间的银盘磁场结构。此前帕克斯脉冲星观测已揭示近邻旋臂与臂间区域存在磁场反转现象。我们希望借助UWL接收器更高的灵敏度，将此类研究拓展至更遥远的区域，从而能更清晰地区分银盘磁场结构的不同模型。由于基于色散量（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进行平均，才能可靠地证明磁场反转的存在。这项工作将对银盘磁场生成理论及其他领域（如宇宙线物理）具有重要意义——这些领域的解释依赖于对大尺度银盘磁场的认知。