Parkes observations for project P1328 semester 2024OCTS_02

Fast radio bursts are peculiar micro-millisecond duration transients, which have been seen to be extragalactic in origin. Since their discovery, a dichotomy has emerged in their population. Some FRBs have been seen to be repeating, while others have not been seen to be repeating. The repeating FRBs, such as FRB 20180301A, provide an unparalleled window into their circumburst environment due to their repeating nature, which can be used to constrain possible progenitor models and test underlying emission mechanisms. Additionally, FRB 20180301A has been seen to have interesting polarisation properties, such as a switch in the sign of RM, indicating a reversal in the magnetic field and a marked reduction in the linear polarisation fraction towards lower frequencies (depolarisation). The previous Parkes/Murriyang source follow-up has also revealed a temporal evolution in the dispersion measure (DM) of the source and tentative evidence for correlation in the DM and rotation measure (RM). The ultra-wideband low (UWL) receiver on Parkes/Murriyang is ideally suited to explore the wideband spectro-temporal and polarimetric behaviour of the source. We propose regular monitoring of FRB 20180301A using UWL to model the magnetic field evolution, study its circumburst media using depolarisation behaviour, and constrain any correlation of DM and RM.

快速射电暴（Fast Radio Bursts, FRB）是一类特殊的微毫秒级持续时间瞬变源，现已证实其起源于河外天体。自被发现以来，其种群呈现出鲜明的二分性：部分FRB表现出重复爆发特性，另一部分则未观测到重复爆发。诸如FRB 20180301A的重复快速射电暴，凭借其重复爆发的特质，为研究其爆发周围环境提供了无可比拟的观测窗口，可用于约束潜在的前身星模型并检验核心辐射机制。此外，FRB 20180301A展现出引人关注的偏振特性，例如旋转量度（Rotation Measure, RM）的符号发生反转，这表明其周围磁场出现逆转；同时在较低频率下，线偏振分量占比显著降低（即去偏振现象）。此前针对该源的帕克斯/穆里扬（Parkes/Murriyang）望远镜后续观测，还揭示了其色散量度（Dispersion Measure, DM）随时间的演化特征，以及DM与RM存在相关性的初步证据。帕克斯/穆里扬望远镜搭载的超宽带低频（Ultra-Wideband Low, UWL）接收机，非常适合用于探究该源的宽频谱时演化与偏振特性。本研究拟利用UWL接收机对FRB 20180301A开展常态化监测，以建模其磁场演化过程、通过去偏振现象研究其爆发周围介质，并约束DM与RM之间的相关性。