Long-term Monitoring of the Repeating Fast Radio Burst 20220912A with the uGMRT at Low Radio Frequencies

Some repeating fast radio bursts (FRBs) exhibit occasional extreme repetition rates, but very few show a sustained high activity level. One such hyperactive repeater is FRB 20220912A, which was discovered by CHIME/FRB Collaboration on 2022 September 12. Here, we present results from a long-term monitoring campaign of FRB 20220912A using the upgraded Giant Metrewave Radio Telescope (uGMRT) in the frequency range from 300 to 750 MHz. Over the course of nearly two years, we detected a total of 643 bursts in this frequency range. The source exhibited extreme activity for a few months after its discovery and sustained its active phase for more than 1.5 yr, with unsystematic modulations in the activity during this phase. The cumulative energy distributions in both bands show a break, consistent with other active repeaters such as FRB 20121102A, FRB 202011124A, etc., suggesting common underlying emission mechanisms. Moreover, we show that the shape of the energy distribution for FRB 20220912A remains broadly the same across a large range of frequencies and over time. Overall, the extended high activity, estimated total energy output, persistent power-law tails in the energy distributions, and lack of detectable short-timescale periodicity favor progenitor models invoking young dynamic magnetars, potentially emitting pulses across large ranges of rotation phase.