Machine learning classification of baseband data of CHIME FRBs

TL;DR

This paper applies machine learning to high-resolution baseband data from CHIME/FRB to classify FRBs, identifying new repeater candidates and refining previous classifications, thereby aiding understanding of their origins.

Contribution

The study leverages high-resolution baseband data and machine learning to improve FRB classification accuracy and discover new repeater candidates, surpassing prior intensity-based analyses.

Findings

Identified 15 new repeater candidates among 122 non-repeating FRBs.

Reclassified 31 previously labeled candidates as non-repeaters.

Confirmed one candidate as a repeater, emphasizing the method's effectiveness.

Abstract

Fast Radio Bursts (FRBs) are bright millisecond radio pulses. Their origin is still unknown in the field of astronomy. A notable distinction among FRBs is that some sources repeat, while others appear to be non-repeating events. Interestingly, repeating FRBs tend to exhibit broader temporal widths and narrower spectral bandwidths compared to non-repeat events, suggesting they may arise from different physical mechanisms. However, current radio telescopes have limited coverage and sensitivity, which hinders a complete survey with continuous long-term monitoring. This issue makes it difficult to confirm repeat activity and potentially leads to misclassification of repeaters as non-repeaters; these are referred to as repeater candidates. To address this, machine learning techniques have emerged as a useful tool for classifying distinct FRB types in previous studies. In this study, we utilize the CHIME/FRB baseband catalog with three orders of magnitude better time resolution than the intensity catalog. Measured fluences are available in the baseband catalog, while only upper limits are reported in the intensity catalog. We apply machine learning to the baseband catalog to evaluate classification outcomes. We identify 15 repeater candidates among 122 non-repeating FRBs in the baseband catalog. Additionally, our classification identifies 31 sources previously categorized as repeater candidates as non-repeaters, highlighting a significant difference from the prior work. Of these repeater candidates, 14 overlap with previous findings, while 1 is newly identified in this work. Notably, one of our candidates was confirmed as a repeater by CHIME/FRB. Follow-up observations for the 14 candidates are highly encouraged.