Radio Monitoring Campaign of Active Repeater FRB 20220912A with CHIME

TL;DR

This paper presents a detailed radio monitoring campaign of the highly active repeating FRB 20220912A using CHIME, analyzing 828 bursts over 1.5 years, revealing bimodal wait times, energy estimates, and DM evolution.

Contribution

First comprehensive long-term radio monitoring of FRB 20220912A, providing insights into its activity, burst properties, and local environment evolution.

Findings

Detected 828 bursts over 1.5 years with bimodal wait-time distribution.

Estimated total emitted energy of $2 imes 10^{43}$ ergs for the source.

Observed a 2.3σ linear increase in DM over time, with no significant RM trend.

Abstract

FRB 20220912A is a highly active repeating fast radio burst (FRB) source, discovered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) using its real-time FRB detection system (CHIME/FRB). Here, we present results from a radio monitoring campaign of FRB 20220912A using CHIME, including ~200 hours of data collected by CHIME/Pulsar, spanning 1.5 years following the source's discovery. We present an analysis of a sample of 828 CHIME-detected bursts from FRB 20220912A, in the 400-800 MHz radio frequency band. The source remains highly active for ~10 weeks and has a bimodal wait-time distribution with peaks at $160^{+120}_{-70}$ ms and $306^{+14}_{-13}$ s. Assuming a radio efficiency factor of $10^{-4}$ and a beaming angle of 0.1, we estimate the total emitted energy from the source over the entire observing campaign to be $2 \times 10^{43}$ ergs. We report a 2.3$\sigma$ detection of a linear increase in the DM of $1.4 \pm 0.6$ pc cm$^{-3}$ yr$^{-1}$, with no significant trend in rotation measure (with a 3$\sigma$ upper limit of 13.4 rad m$^{-2}$ yr$^{-1}$). We contrast our findings with other active repeaters, which exhibit different DM and RM evolution to indicate that FRB 20220912A may reside in a unique local environment.