Parkes observations for project P958 semester 2019OCTS_21

Fast radio bursts (FRBs) continue to raise more questions than they answer. Until last year, only one burst – the only one known to repeat - had been localized to a bright radio nebula (either a young supernova remnant or pulsar wind nebulae) in a distant dwarf galaxy. Over the last two year searches with the Australian Square Kilometre Array Pathfinder (ASKAP) have detected 31 bursts, five of which have been localised to host galaxies at redshifts ranging from 0.1 to 0.5. These bursts and their hosts are very unlike the repeater, suggesting there may be a dichotomy in the population. However one of the arcminute-localised ASKAP FRBs has recently been found to repeat. Here we propose to search and study repetitions in this FRB population. Our comprehensive sample and a dense monitoring campaign of well localised bursts, at a fluence limit more than 60 times lower than that of their detections to characterise the fraction of bursts that repeat. For bursts that repeat the unique wide bandwidth observations will be used to test leading models of burst emission.

快速射电暴（Fast Radio Bursts, FRBs）迄今引发的疑问远多于其已厘清的问题。直至去年，人类仅发现一例可重复爆发的射电暴，并将其精确定位至遥远矮星系内的明亮射电星云——该星云或为年轻超新星遗迹，或是脉冲星风云星云。过去两年间，依托澳大利亚平方千米阵探路者（Australian Square Kilometre Array Pathfinder, ASKAP）开展的巡天探测已累计发现31例快速射电暴，其中5例被定位至红移值介于0.1至0.5之间的宿主星系。此类射电暴及其宿主星系与此前发现的重复暴特征差异显著，暗示该类暴源群体或存在二分性。不过，近期研究发现，一例经ASKAP完成角分级别定位的FRB同样存在重复爆发行为。基于此，本研究计划对该类FRB群体开展重复爆发特征的搜寻与系统性研究。我们将通过构建全面的样本库，以及针对精确定位射电暴的高密度监测计划，将能流探测极限降至此前检测水平的1/60以下，以此量化存在重复爆发行为的射电暴占比。对于存在重复爆发的射电暴，我们将借助独有的宽带宽观测数据，检验当前主流的射电暴辐射模型。