# What if the fast radio bursts 110220 and 140514 are from the same source?

## TL;DR

This paper explores the possibility that two seemingly unrelated fast radio bursts are from the same neutron star within a supernova remnant, using evolving dispersion measure data to support the hypothesis.

## Contribution

It introduces a model linking FRB DM variations to supernova remnant expansion, providing constraints on the supernova's age, ejecta mass, and explosion energy, and suggests a method to test the young neutron star hypothesis.

## Key findings

- The supernova must have occurred within approximately 10.2 years of the first FRB.
- Constraints favor a stripped-envelope (Type Ib/c) supernova and/or a very energetic explosion.
- Future FRB repetitions could help disentangle the DM contributions from the SNR and other sources.

## Abstract

The fast radio bursts (FRBs) 110220 and 140514 were detected at telescope pointing locations within 9 arcmin of each other over three years apart, both within the same 14.4 arcmin beam of the Parkes radio telescope. Nevertheless, they generally have not been considered to be from the same source because of a vastly different dispersion measure (DM) for the two bursts by over $380\,{\rm pc\,cm^{-3}}$. Here we consider the hypothesis that these two FRBs are from the same neutron star embedded within a supernova remnant (SNR) that provides an evolving DM as the ejecta expands and becomes more diffuse. Using such a model and the observed DM change, it can be argued that the corresponding SN must have occurred within $\approx10.2$ years of FRB 110220. Furthermore, constraints can be placed on the SN ejecta mass and explosion energy, which appear to require a stripped envelope (Type Ib/c) SN and/or a very energetic explosion. A third FRB from this location would be even more constraining, allowing the component of the DM due to the SNR to be separated from the unchanging DM components due to the host galaxy and intergalactic medium. In the future, if more FRBs are found to repeat, the sort of arguments presented here can be used to test the young neutron star progenitor hypothesis for FRBs.