Parkes observations for project P1328 semester 2024APRS_08

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）是一类奇特的微毫秒级持续时间瞬变天体，现已被证实均起源于河外星系。自其被发现以来，该类天体的观测样本呈现出明确的二分特征：部分快速射电暴被观测到具有重复爆发特性，其余则未表现出重复爆发行为。
重复爆发快速射电暴（如FRB 20180301A）凭借其重复爆发的特性，为研究其暴周环境提供了独一无二的窗口，可用于约束各类可能的前身天体模型，并检验其核心辐射机制。此外，FRB 20180301A展现出极具研究价值的偏振特性，例如旋转量（Rotation Measure, RM）符号发生切换，这表明其磁场出现反转，且随着频率降低，线偏振度显著下降，即消偏振现象。
此前针对该源的帕克斯/穆里扬（Parkes/Murriyang）望远镜后续观测研究，还揭示了该源的色散量（Dispersion Measure, DM）随时间演化的特征，以及色散量与旋转量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低频宽带（Ultra-Wideband Low, UWL）接收机，极其适合用于探究该源的宽带光谱时域行为与偏振特性。本研究提议利用UWL接收机对FRB 20180301A开展常态化监测，以建模其磁场演化过程、通过消偏振特性研究其暴周介质，并约束色散量与旋转量之间的相关性。