A broad survey of spectro-temporal properties from FRB 20121102A

Abstract

We survey the spectro-temporal properties of fast radio bursts from FRB 20121102A observed by earlier studies across a wide range of frequencies. We investigate 167 bursts from FRB 20121102A spanning frequencies 1--7.5GHz, durations of less than 1 ms to approximately 10 ms, with low and high energies, and with different wait-times. We find from this sample of bursts a strong agreement with the inverse relationship between sub-burst slope and duration and with other predictions made by the triggered relativistic dynamical model (TRDM). Earlier results found agreement with those predictions across three different repeating FRB sources. For this sample of bursts, we find that the sub-burst slope as well as the 'sad trombone' drift rate are consistent with being in a quadratic relationship with frequency and that both these quantities are inversely proportional to the duration. We also find that the duration decreases with increasing frequency as well as a statistically significant correlation between the sub-burst duration and bandwidth (proportional to $t^{-1/2}$) that is unexpected. No distinct group of bursts in this sample deviated from these relationships, however significant scatter can be seen in measurements. This study demonstrates the consistent existence of relationships between the spectro-temporal properties of bursts from a repeating FRB source. A simple explanation for the inverse relation between the sub-burst slope and duration is an inherently narrowband emission process. We make all measurements available as well as a graphical user interface called Frbgui developed and used to perform measurements of burst waterfalls.