A Time-domain Study of Repeat and Nonrepeat Fast Radio Bursts

Abstract Fast radio bursts (FRBs) are extremely energetic radio transients, typically classified as repeat or nonrepeat, but their origins remain uncertain. In this work, we focus on the timing characteristics of the pulses in 536 FRBs observed by CHIME with improved pulse-finding and fitting algorithms. The results show that the fitted mean of rise time, decay time, FWHM, and minimum variable timescale distributions for the repeat FRBs are larger. Furthermore, the Kolmogorov–Smirnov test reveals significant differences (>5 σ ) for some parameters between repeat and nonrepeat FRBs, implying that the former may have more stable and longer-lived sources (e.g., magnetars). However, we do not find significant differences in waiting times, which may be a limitation of the sample. We also investigate the relationship between these parameters, identifying some correlations, e.g., a negative power-law correlation between pulse amplitude and FWHM. Our findings suggest that the repeat and nonrepeat FRBs originate from different progenitors, environments, and/or emission mechanisms. Interestingly, both of their observations do not contradict that they originate from within the magnetosphere of a magnetar.