A lensed FRB candidate in the first CHIME/FRB Catalogue and its potential implications

TL;DR

This paper reports the identification of a potential gravitationally lensed fast radio burst in the CHIME/FRB catalogue, using autocorrelation analysis and lens modeling, which could have significant implications for understanding FRB environments and cosmology.

Contribution

The study introduces an autocorrelation-based method to detect lensed FRBs and constrains the lensing object’s mass, marking a novel approach in FRB lensing searches.

Findings

FRB 20190308C is a candidate for gravitational lensing with 3.4 sigma significance.

The lensing object’s mass was constrained using the Chang-Refsdal lens model.

Future observations could reveal more lensed FRBs and enhance understanding of their origins.

Abstract

Fast radio bursts (FRBs) are immensely energetic radio pulses with durations of milliseconds. Given their high all-sky rate, the probability of an FRB being lensed by an intervening massive object is non-negligible. In this study, we search for possible lensing candidates within the first Canadian Hydrogen Intensity Mapping Experiment FRB catalogue using an autocorrelation algorithm and verification through signal simulations. We identify FRB 20190308C as a lensed candidate with a significance of 3.4 sigma. Furthermore, we constrain the mass of the lensing object using the Chang-Refsdal lens model, based on the flux ratio and time delay between the substructures of FRB 20190308C. Future long-term and high-precision observations are expected to reveal more lensed FRBs.