标题： CHIME/FRB 第一目录中的快速射电暴形态学 显示英文标题

标题： Fast Radio Burst Morphology in the First CHIME/FRB Catalog

摘要： 我们展示了加拿大氢强度测绘实验（CHIME）快速射电暴（FRB）项目在400-800 MHz频段内探测到的FRB形态学特征（即流量随时间和频率的变化），使用的是来自第一个CHIME/FRB目录中的事件。该目录包括从2018年7月25日至2019年7月2日之间检测到的18个重复源的61次爆发以及474次单次FRB。我们识别出四种观测到的爆发形态学原型（“简单宽带”、“简单窄带”、“时间复杂”和“向下漂移”），并描述了解释观测到的形态学所必需的相关仪器偏倚。利用这些FRB的目录特性，我们证实了来自重复源的爆发平均具有更大的宽度，并首次表明来自重复源的爆发平均而言带宽更窄。这种差异可能是由于束流效应或传播效应，也可能是源于不同群体本身。我们讨论了这些形态学差异可能对将FRB作为天体物理工具带来的潜在影响。 显示英文摘要

摘要： We present a synthesis of fast radio burst (FRB) morphology (the change in flux as a function of time and frequency) as detected in the 400-800 MHz octave by the FRB project on the Canadian Hydrogen Intensity Mapping Experiment (CHIME/FRB), using events from the first CHIME/FRB catalog. The catalog consists of 61 bursts from 18 repeating sources, plus 474 one-off FRBs, detected between 2018 July 25 and 2019 July 2. We identify four observed archetypes of burst morphology ("simple broadband," "simple narrowband," "temporally complex" and "downward drifting") and describe relevant instrumental biases that are essential for interpreting the observed morphologies. Using the catalog properties of the FRBs, we confirm that bursts from repeating sources, on average, have larger widths and we show, for the first time, that bursts from repeating sources, on average, are narrower in bandwidth. This difference could be due to a beaming or propagation effects, or it could be intrinsic to the populations. We discuss potential implications of these morphological differences for using FRBs as astrophysical tools.