论文标题
FRB 121102：爆发极化的急剧变化与持续发射的稳定性形成对比
FRB 121102: drastic changes in the burst polarization contrasts with the stability of the persistent emission
论文作者
论文摘要
我们研究了持续的无线电对应物与FRB 121102的MilliarcSecond尺度特性，并研究了明亮爆发的光偏光特性。对于前者，我们在2017年使用1.7和4.8 GHz的欧洲VLBI网络（EVN）观察结果。对于后者，我们从2016年拍摄的100 m Effelseberg望远镜中重新分析了1.7-GHz数据。这些观察结果早于FRB 121102的其他极化研究，并产生最高的爆发法拉第旋转度量（RM），迄今为止，RM = 1.27*10^5 M^-2 rad-M^-2，一致，一致降低。在1.7 GHz时，爆发发射的分数极化为15％。如果爆发环境的法拉第宽度为150 rad m^-2-裸露的法拉第旋转的0.1％，则可以将其与较高频率的高分数极化对帐。该宽度可能起源于法拉第屏幕中的次要非均匀性，也可能来自发射区域本身的效果。持续源大小的上限为1 pc，与年轻的超新星（SN）场景几乎一致。范围可变性限制<10％不支持年轻的SN情景，也挑战了其他解释。微弱的持续源的分数极化在4.8 GHz时限制为<25％，排除了高度极化的个体爆发的共同起源。
We study milliarcsecond-scale properties of the persistent radio counterpart to FRB 121102 and investigate the spectro-polarimetric properties of a bright burst. For the former, we use European VLBI Network (EVN) observations in 2017 at 1.7 and 4.8 GHz. For the latter, we re-analyse the 1.7-GHz data from the 100-m Effelseberg telescope taken in 2016. These observations predate other polarimetric studies of FRB 121102, and yield the highest burst Faraday rotation measure (RM) to date, RM = 1.27*10^5 rad m^-2, consistent with the decreasing RM trend. The fractional polarization of the burst emission is 15% at 1.7 GHz. This can be reconciled with the high fractional polarization at higher frequencies if the Faraday width of the burst environment is 150 rad m^-2 - a bare 0.1% of the total Faraday rotation. The width may originate from minor non-uniformities in the Faraday screen, or from effects in the emitting region itself. The upper limit on the persistent source size is 1 pc, barely consistent with a young supernova (SN) scenario. The flux variability limit of <10% is not in favor of the young SN scenario, and challenges other interpretations as well. The fractional polarization of the faint persistent source is constrained at <25% at 4.8 GHz ruling out a common origin with the highly polarized individual bursts.
