Parkes observations for project P1068 semester 2020APRS_29

In the fast-moving world of Fast Radio Bursts (FRBs), the key question of what fraction (as high as 100%?) of FRBs emit repeat bursts remains unanswered. Of order 10 repeating FRBs are now known, and their spectro-temporal properties hint at differences with apparently non-repeating bursts - but poor statistics preclude a definitive diagnosis. FRB 180301 is a promising source for further study for multiple reasons: it is the first repeating FRB seen by the FAST telescope, and has the second-highest rotation measure ever seen for a FRB (after the original repeater, FRB121102). We request Parkes observations with the UWL to characterise the broadband emission properties of this FRB, with the following key goals: to constrain the repetition rate, identify any variation of pulse characteristics over time, and provide insight into the emission mechanisms. In its initial detection, FRB 180301 was poorly fit by regular Faraday rotation models, and showed significant circular polarization, which may indicate the progenitor is embedded in an extreme magneto-ionic environment with complex field structure that has not been seen before. These observations will generate a large data volume. We will use the Medusa backend in parallel with the Breakthrough Listen data recorder (BL), and will transfer data to BL immediately after observations.These data will be used by P. Kumar to prototype a FRB pipeline for the UWL, that will be made broadly available for similar studies.

在快速射电暴（Fast Radio Bursts, FRBs）快速发展的研究领域中，一个核心悬而未决的问题是：究竟有多大比例（最高可达100%？）的快速射电暴会产生重复爆发信号。目前已知的重复快速射电暴仅约10例，它们的谱时特性似乎与非重复暴存在差异，但受限于统计样本不足，无法得出确定性结论。

FRB 180301是多维度具备进一步研究价值的优质源：它是首个被500米口径球面射电望远镜（Five-hundred-meter Aperture Spherical radio Telescope, FAST）探测到的重复快速射电暴，其旋转测度（rotation measure）在已知快速射电暴中位列第二，仅次于首例重复暴FRB 121102。我们申请使用帕克斯（Parkes）望远镜结合UWL设备开展观测，以刻画该快速射电暴的宽频辐射特性，核心目标包括：约束重复爆发率、探究脉冲特性随时间的变化规律，以及为辐射机制研究提供深入洞察。

在最初的探测中，常规法拉第旋转模型无法较好拟合FRB 180301的观测数据，且其表现出显著的圆偏振特性，这或许意味着其前身天体处于此前未被观测到的极端磁离子环境中，且拥有复杂的磁场结构。

本次观测将产生海量数据。我们将并行使用Medusa后端与突破聆听（Breakthrough Listen, BL）数据记录仪开展观测，并在观测结束后立即将数据传输至BL团队。P. Kumar将利用这批数据为UWL搭建一套快速射电暴数据处理流程原型，该原型将面向同类研究广泛开放共享。