Parkes observations for project P1068 semester 2020APRS_07

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.

快速射电暴（Fast Radio Bursts, FRBs）研究领域日新月异，但一个核心问题始终悬而未决：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。目前已知的重复快速射电暴仅约10例，它们的谱时特性暗示其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是极具研究价值的候选源，原因有多方面：它是FAST望远镜发现的首例重复快速射电暴，且拥有迄今为止第二高的射电暴旋转量度（rotation measure），仅次于首例重复暴FRB 121102。我们申请使用帕克斯（Parkes）望远镜搭载UWL开展观测，以表征该快速射电暴的宽带辐射特性，核心科学目标包括：约束重复爆发率、探究脉冲特性随时间的演化规律，以及深入解析其辐射机制。在最初的探测中，常规法拉第旋转（Faraday rotation）模型无法很好拟合FRB 180301的观测数据，且其表现出显著的圆偏振（circular polarization）特征，这或许暗示其前身天体嵌入在一种前所未见的、具有复杂磁场结构的极端磁离子环境中。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）数据记录系统（BL）开展数据采集，并在观测结束后即刻将数据传输至BL。这些数据将由P. Kumar用于研发适配UWL的快速射电暴数据处理流水线，该流水线后续将面向同类研究广泛开放使用。