2020ApJ...902L..17T

Despite many searches for periodicity in the repeating fast radio burst FRB 121102, the underlying pattern of bursts does not appear to be a periodic one. We report a logarithmic repetition pattern in FRB 121102 in the sense that the rate falls off inversely with time for each set of bursts. This result implies that repeating fast radio burst sources are not necessarily associated with a pulsar, but rather could be caused by a different type of phenomenon that involves an equal amount of energy output per log time.