Parkes observations for project P1195 semester 2023APRS_01

Repeating sources of fast radio bursts (FRBs) have enabled numerous breakthroughs in our understanding of the universe, as well as key insight into the progenitors of these enigmatic events. Compared to the thousands of known FRBs, there are only a handful that are known to repeat. From this small sample, it has become apparent that the emission properties of repeating events may be fundamentally different from one-off events, with repeating FRBs demonstrating downward-drifting sub-bursts and narrow bandwidth emission. It is unclear what percentage of repeating FRBs have these characteristics and if the observed differences represent intrinsic differences in FRB populations, if it is caused by a propagation effect related to local environments, or if it is due to as yet to be understood selection effects. A larger population of repeating FRBs would enable statistical studies of these phenomena and answer where repeat events fit in the larger FRB ecosystem. This proposal aims to observe and identify additional repeat FRBs by targeting events that have demonstrated the aforementioned emission properties, as observed by Canadian Hydrogen Intensity Mapping Experiment FRB (CHIME/FRB). Parkes/Murriyang's and CHIME's fields of view overlap between +25 and -11 degrees latitude and given CHIME's success at detecting thousands of FRBs, there are many targets that are visible to both telescopes. Given the likelihood of non-detections, this project proposes to only observe in unallocated time which would otherwise go unused, therefore increasing the scientific impact of Murriyang while also building upon our understanding of these enigmatic events.

快速射电暴（FRB）的重复源为我们理解宇宙带来了诸多突破，也为探究这些神秘事件的起源天体提供了关键洞见。与已知的数千个FRB相比，已确认的重复FRB仅有寥寥数个。从这一小样本中可明显看出，重复事件的辐射特性可能与一次性事件存在本质差异——重复FRB呈现出频率向下漂移的子爆发及窄带宽辐射特征。目前尚不清楚有多少比例的重复FRB具备这些特征，也不确定观测到的差异是FRB群体的固有差异、由局部环境相关的传播效应导致，还是源于尚未明确的选择效应。更大规模的重复FRB样本将为这些现象的统计研究提供可能，并解答重复事件在整个FRB生态系统中的定位问题。本提案旨在通过观测加拿大氢强度映射实验FRB项目（CHIME/FRB）已探测到的、具有上述辐射特性的事件，来观测并识别更多重复FRB。Parkes/Murriyang望远镜与CHIME的视场在纬度+25°至-11°之间存在重叠区域；鉴于CHIME在探测数千个FRB方面的成功经验，存在大量两台望远镜均可观测到的目标源。考虑到探测失败的可能性，本项目建议仅使用原本闲置的未分配观测时间开展观测，从而在提升Murriyang望远镜科学影响力的同时，进一步深化我们对这些神秘事件的理解。