Parkes observations for project P1338 semester 2024OCTS_27

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）是起源于河外空间的毫秒级持续时长射电暴。自首例FRB在帕克斯/穆里扬多波束存档数据中被发现以来，该类暴源的种群已显现出清晰的二分特征：尽管已利用多台不同射电望远镜开展了大量后续观测工作，但部分FRB表现出重复爆发特征，另一类则未观测到重复爆发现象。近日，CHIME/FRB项目发现了重复快速射电暴FRB 20240114A，该源展现出极高的爆发活跃度，此类极端活跃的爆发行为在其他任何已知FRB源中均未被观测到。由于具备重复爆发的特性，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观测窗口，可用于约束潜在的前身星模型，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工作，还揭示了多项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（即色差特性）、潜在的暴源活动窗口、显著的高圆偏振（Circular Polarisation, CP）以及圆偏振的频率依赖特性。这些特性是解析FRB暴周环境、验证各类前身星模型的关键所在。搭载可靠偏振测量功能的大带宽观测仪器，是揭示此类特性的核心前提。帕克斯/穆里扬望远镜搭载的超宽带低频（Ultra-Wideband Low, UWL）接收机，恰好可用于深入探究该源的宽频带光谱时域与偏振演化特性。我们提议开展一项针对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。