Distribution of fast radio burst dispersion measures in CHIME/FRB Catalog 1: implications on the origin of FRBs

TL;DR

This study analyzes the dispersion measure distribution of FRBs from the CHIME/FRB Catalog 1 to infer their origin, suggesting they may originate from young magnetars due to their redshift evolution.

Contribution

It applies the M&E 2018 model to the largest FRB catalog to estimate the redshift evolution parameter, providing new insights into FRB origins.

Findings

FRB population evolution is consistent with star formation rate.

Estimated evolution parameter n is near zero, indicating no strong evolution.

Results support the hypothesis of FRBs originating from young magnetars.

Abstract

Recently, CHIME/FRB project published its first fast radio burst (FRB) catalog (hereafter, Catalog 1), which totally contains 536 unique bursts. With the help of the latest set of FRBs in this large-size catalog, we aim to investigate the dispersion measure (DM) or redshift ($z$) distribution of the FRB population, and solution of this problem could be used to clarify the question of FRB origin. In this study, we adopted the M\&E 2018 model, to fit the observed $z$ distribution of FRBs in Catalog 1. In the M\&E 2018 model, we are mostly interested in the $\Phi(z)$ function, i.e., number of bursts per proper time per comoving volume, which is represented by the star formation rate (SFR) with a power-law index $n$. Our estimated value of $n$ is $0.0_{-0.0}^{+0.6}$ ($0.0_{-0.0}^{+2.1}$) at the 68 (95) per cent confidence level, implying that the FRB population evolves with redshift consistent with, or faster than, the SFR. Specially, the consistency of the $n$ values estimated by this study and the SFR provides a potential support for the hypothesis of FRBs originating from young magnetars.