Parkes observations for project P1328 semester 2024APRS_21

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, FRBs）是一类特殊的微毫秒级持续时间瞬变源，现已被证实起源于河外天体。自其被发现以来，该类源的种群呈现出明显的二分性：部分FRB表现出重复爆发特性，而另一部分则未观测到重复爆发。以FRB 20180301A为代表的重复快速射电暴，凭借其重复爆发的特性，为研究暴周环境提供了无可比拟的窗口，可用于约束相关前身星模型并检验核心辐射机制。此外，观测显示FRB 20180301A具备独特的偏振特性，例如旋转量（Rotation Measure, RM）符号发生反转，这表明其磁场出现逆转，且在低频段线偏振度显著降低（即退偏振现象）。此前针对该帕克斯/穆里扬望远镜源的后续观测，还揭示了其色散量（Dispersion Measure, DM）随时间的演化特征，以及DM与RM之间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段（UWL）接收机，非常适合用于探究该源的宽频段时频与偏振特性。我们提议利用该UWL接收机对FRB 20180301A开展定期监测，以建模其磁场演化过程、通过退偏振现象研究其暴周介质，并约束DM与RM之间的相关性。