Parkes observations for project P1338 semester 2024OCTS_45

Fast radio bursts (FRBs) are millisecond-duration radio bursts of extragalactic origin. Since the discovery of the first FRB in the archival Parkes/Murriyang multibeam data, a broad dichotomy in population has emerged. Some FRBs have been seen to be repeating, while others are not, despite a significant amount of follow-up using different radio telescopes. The repeating FRB 20240114A was recently discovered by CHIME/FRB, which has been seen to have an exceptionally high burst activity. Such extreme burst activity has not been seen in any other source. The repeating FRBs, such as FRB 20240114A, 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. The previous Parkes/Murriyang source follow-up has also revealed intriguing spectro-polarimetric properties, such as frequency-dependent evolution of burst central frequency or chromaticity, a possible activity window, significantly large circular polarisation (CP), and frequency-dependent CP. These properties hold the key towards understanding the circumburst environment of the FRBs, and test possible progenitor models. A large bandwidth instrument with reliable polarimetry has been critical in uncovering these properties. The ultra-wideband low (UWL) receiver on Parkes/Murriyang is ideally suited to explore the source's wideband spectro-temporal and polarimetric behaviour. We propose a campaign to regularly follow up FRB 20240114A to ascertain its long-term evolution of spectro-temporal properties.

快速射电暴（Fast Radio Bursts, FRBs）是起源于河外的毫秒级射电爆发。自首个FRB在帕克斯（Parkes）/穆里扬（Murriyang）多波束存档数据中被发现以来，该类暴的族群已呈现出显著的二分特性：尽管已借助多台不同射电望远镜开展了大量后续观测，但部分FRB表现出重复爆发特征，另一部分则无重复爆发现象。近期由CHIME/FRB项目发现的重复暴FRB 20240114A，展现出异常高的爆发活跃度，这一极端爆发行为在其他任何天体源中均未被观测到。得益于重复爆发的固有特性，诸如FRB 20240114A这类重复快速射电暴，为探究其暴周环境提供了无可比拟的研究窗口，可用于约束可能的前身天体模型并检验其核心辐射机制。此前针对帕克斯/穆里扬望远镜观测源的后续研究，还揭示了诸多极具研究价值的光谱偏振特性，例如爆发中心频率的频率依赖演化（即色散特性）、潜在的活动窗口、显著的高圆偏振（Circular Polarisation, CP）以及与频率相关的圆偏振现象。这些特性是破解FRB暴周环境谜团、验证各类可能前身天体模型的关键所在。具备可靠偏振测量能力的大带宽观测仪器，在揭示这些特性的过程中发挥了至关重要的作用。帕克斯/穆里扬望远镜搭载的超宽频低波段（Ultra-wideband Low, UWL）接收机，非常适合用于探索该源的宽频光谱时域与偏振行为特征。我们提议开展一项长期后续观测计划，定期对FRB 20240114A进行监测，以明确其光谱时域特性的长期演化规律。