Parkes observations for project P1343 semester 2025APRS_06

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 commissioning of new dedicated FRB detection systems has led to an exponential increase in the detected FRBs over the last decade. Despite >700 FRBs published to date, there is still a lack of understanding about the physical mechanisms through which FRB emission is produced. Due to the possibility of detecting multiple bursts from the same source in a repeating FRB, it forms an ideal sample set to uncover the physics of the source (e.g., emission mechanism, progenitor surrounding media), and test possible progenitor models. The coherent upgrade to the FRB detection system to ASKAP is expected to detect ~1-2 FRB/week. However, due to the limited fractional bandwidth available with ASKAP and survey nature of the telescope, probing the spectro-polarimetric characteristics of repeating sources is non-optimal. Hence, the large bandwidth offered by the ultra wideband-low (UWL) on Parkes/Murriyang is an ideal instrument to follow-up repeating FRB sources discovered through CRACO. Over the next ~6 months, we expect to double the number of repeaters that have been studied through the UWL. This will provide unprecedented insight into the progenitor environment and the surrounding media of repeating FRBs. We propose using the UWL to follow up repeater-like sources to study their wideband spectro-polarimetric characteristics.

快速射电暴（Fast Radio Bursts, FRBs）是一类起源于河外星系、持续时长仅为数毫秒的射电暴。自首次在帕克斯/穆里扬射电望远镜（Parkes/Murriyang）的存档多波束数据中发现第一例快速射电暴以来，该类暴源群体便呈现出显著的二分特征：尽管学界已借助多台不同射电望远镜开展大量后续观测，但部分快速射电暴被证实会重复爆发，另一部分则仅出现单次爆发。近十年来，多款专用快速射电暴探测系统的调试启用，使得已探测到的快速射电暴数量呈指数级增长。尽管迄今已有超700例快速射电暴被正式发表，学界对其辐射产生的物理机制仍未形成充分认知。由于重复暴可观测到同一暴源的多次爆发事件，因此成为揭示暴源物理本质（如辐射机制、前身天体周围介质）、验证各类潜在前身天体模型的理想样本集。针对快速射电暴探测系统的ASKAP相干升级改造，预计可实现每周探测1~2例快速射电暴。然而，由于ASKAP望远镜的可用分数带宽有限，且其定位为巡天观测望远镜，利用其开展重复暴源的光谱偏振特性研究并非最优方案。因此，帕克斯/穆里扬射电望远镜搭载的超宽带低频（Ultra Wideband-Low, UWL）系统，是对CRACO项目发现的重复快速射电暴源开展后续观测的理想设备。未来约6个月内，我们预计借助UWL系统开展研究的重复暴源数量将实现翻倍，这将为深入理解重复快速射电暴的前身天体环境及其周围介质提供前所未有的契机。我们提议利用UWL系统对疑似重复爆发的暴源开展后续观测，以研究其宽带光谱偏振特性。