Parkes observations for project P1338 semester 2024OCTS_25

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时长射电暴。自科研人员在帕克斯/穆里扬多波束存档数据中发现首例快速射电暴以来，该天体群体逐渐显现出清晰的二分特性：尽管学界已借助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证实会重复爆发，其余则仅出现单次爆发。近日，CHIME/FRB项目组发现了重复爆发的快速射电暴20240114A，该暴展现出异常高的爆发活跃度，迄今为止尚未在其他任何快速射电暴源中观测到如此极端的爆发活动。像20240114A这类重复爆发的快速射电暴，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/穆里扬望远镜观测到的快速射电暴源的后续观测，还揭示了一系列引人关注的光谱偏振特性：例如爆发中心频率的频率依赖性演化（即色偏特性）、可能存在的活动窗口、极强的圆偏振（Circular Polarisation，CP）信号以及圆偏振的频率依赖性。这些特性是解析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。具备可靠偏振测量能力的大带宽观测设备，是揭示上述特性的核心工具。帕克斯/穆里扬望远镜搭载的超宽带低波段（Ultra-Wideband Low，UWL）接收机，恰好能够完美适配该暴的宽频带光谱时域与偏振特性研究。本研究提议启动一项定期后续观测计划，以探明该暴光谱时域特性的长期演化规律。