Revealing the Temporally Stable Bimodal Energy Distribution of FRB 20121102A with a Tripled Burst Set from AI Detections

We performed a deep search on the archival FAST L-band observations during the extreme active phase (from Aug. 2019 to Oct. 2019) of the repeating source FRB 20121102A and obtained a burst sample of 5496 bursts. The burst rate peaked at 456 hr$^{-1}$ during a one-hour observation on September 7th, nearly four times the rate of the previous burst set. The much enhanced completeness enables a refined analysis of the temporal behavior of energy distribution, revealing that the bimodal energy distribution remains stable over time.

It is rather an intrinsic feature of the emission mechanisms than a consequence of co-evolving with the burst rate. The manuscript is under review at Nature Communications and is available on arXiv:2510.07002. Please note that while the dataset linked in this manuscript is now finalized, an updated version of the manuscript PDF is forthcoming.