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

Abstract

Fast Radio Bursts (FRBs) are enigmatic radio pulses whose origins are poorly understood. The dispersion measure of host
galaxy (DMhost) 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 DMhost and its potential correlations with host galaxy parameters,
including redshift, stellar mass, star formation rate (SFR), and galaxy age. Our results reveal that DMhost is consistent with a
log-normal distribution, with the mean ????host = 5.03 ± 0.02 and standard deviation ????host = 0.96 ± 0.03, which corresponds to
a median value Med(DMhost) = exp(????host) = 153 ± 3 pc cm−3
. We find a moderate positive correlation between DMhost and
redshift, but no statistically significant correlations are found between DMhost and stellar mass, SFR, or galaxy age. Our findings
highlight the importance of DMhost as a diagnostic tool for unraveling FRB origins, and underscore the need for future FRB
surveys with deep multiwavelength host galaxy follow-up.