Unveiling the distribution and redshift dependence of host galaxy dispersion measures using localized fast radio bursts

TL;DR

This study analyzes 117 localized FRBs to characterize the distribution of host galaxy dispersion measures and their dependence on redshift, revealing a log-normal distribution and a moderate correlation with redshift.

Contribution

The paper provides the first comprehensive statistical analysis of ${ m DM_{host}}$ for a large sample of localized FRBs, establishing its distribution and correlation patterns.

Findings

${ m DM_{host}}$ follows a log-normal distribution with median 153 pc cm$^{-3}$.

Moderate positive correlation between ${ m DM_{host}}$ and redshift.

No significant correlation between ${ m DM_{host}}$ and galaxy stellar mass, SFR, or age.

Abstract

Fast Radio Bursts (FRBs) are enigmatic radio pulses whose origins are poorly understood. The dispersion measure of host galaxy (${\rm DM_{host}}$) provides critical insights into the local environment of FRB sources. In this study, we analyze a sample of 117 well-localized FRBs to investigate the statistical properties of ${\rm DM_{host}}$ and its potential correlations with host galaxy parameters, including redshift, stellar mass, star formation rate (SFR), and galaxy age. Our results reveal that ${\rm DM_{host}}$ is consistent with a log-normal distribution, with the mean $\mu_{\rm host}=5.03\pm 0.02$ and standard deviation $\sigma_{\rm host} = 0.96\pm 0.03$, which corresponds to a median value ${\rm Med}({\rm DM_{host}})=\exp(\mu_{\rm host})=153\pm 3~{\rm pc~cm^{-3}}$. We find a moderate positive correlation between ${\rm DM_{host}}$ and redshift, but no statistically significant correlations are found between ${\rm DM_{host}}$ and stellar mass, SFR, or galaxy age. Our findings highlight the importance of ${\rm DM_{host}}$ as a diagnostic tool for unraveling FRB origins, and underscore the need for future FRB surveys with deep multiwavelength host galaxy follow-up.