Parkes observations for project P1338 semester 2024OCTS_50

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持续射电暴。自首个快速射电暴在存档的帕克斯/穆里扬（Parkes/Murriyang）多波束数据中被发现以来，其源群已呈现出显著的二分特征：尽管已利用多台不同射电望远镜开展了大量后续观测，但部分快速射电暴被观测到具有重复爆发特性，其余则无此特征。重复快速射电暴20240114A（FRB 20240114A）近日由CHIME/FRB项目发现，其爆发活动强度异常之高，此类极端爆发活动在其他任何源中均未被观测到。诸如FRB 20240114A这类重复快速射电暴，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，可用于约束潜在的前身天体模型并检验核心辐射机制。此前针对帕克斯/穆里扬望远镜观测源的后续研究，还揭示了诸多引人关注的光谱偏振特性：例如爆发中心频率的频率依赖演化（即色散特性）、可能存在的活动窗口、极高的圆偏振（Circular Polarisation，CP），以及圆偏振度随频率变化的现象。这些特性是揭示快速射电暴暴周环境、验证各类潜在前身天体模型的关键所在。搭载可靠偏振测量系统的大带宽观测设备，是揭开此类特性的核心条件。帕克斯/穆里扬望远镜搭载的超宽带低频（Ultra-Wideband Low，UWL）接收机，恰好能够完美适配该源的宽带光谱时域与偏振行为研究。本研究拟开展针对FRB 20240114A的常态化后续观测计划，以明确其光谱时域特性的长期演化规律。