Parkes observations for project P958 semester 2019OCTS_51

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. \r\nOver 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.\r\n 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）引发的疑问远多于其已被解答的问题。直至去年，仅有一种射电暴——也是目前已知唯一会重复爆发的暴——被定位于遥远矮星系中的明亮射电星云（要么为年轻超新星遗迹（supernova remnant），要么为脉冲星风云（pulsar wind nebulae））。
过去两年间，借助澳大利亚平方千米阵列探路者（Australian Square Kilometre Array Pathfinder, ASKAP）开展的巡天探测共发现31次射电暴，其中5次被定位于红移（redshift）范围为0.1至0.5的宿主星系中。这些射电暴及其宿主星系与该重复暴的特征差异显著，暗示射电暴种群可能存在二分性。然而，近期研究发现其中一台经角分精度定位的ASKAP探测快速射电暴存在重复爆发现象。
在此，我们提出针对该FRB种群开展重复暴搜寻与研究的方案：我们将依托完整的样本集，对定位精度较高的射电暴开展高密度监测，其能流密度（fluence）探测下限比此前的探测结果低60倍以上，以此定量表征发生重复爆发的射电暴占比。针对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。