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

Yu Sang, Hai-Nan Lin

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 $μ_{\rm host}=5.03\pm 0.02$ and standard deviation $σ_{\rm host} = 0.96\pm 0.03$, which corresponds to a median value ${\rm Med}({\rm DM_{host}})=\exp(μ_{\rm host})=153\pm 3~{\rm pc~cm^{-3}}$. 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.

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 () 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 and its potential correlations with host galaxy parameters, including redshift, stellar mass, star formation rate (SFR), and galaxy age. Our results reveal that is consistent with a log-normal distribution, with the mean and standard deviation , which corresponds to a median value . We find a moderate positive correlation between and redshift, but no statistically significant correlations are found between and stellar mass, SFR, or galaxy age. Our findings highlight the importance of as a diagnostic tool for unraveling FRB origins, and underscore the need for future FRB surveys with deep multiwavelength host galaxy follow-up.

Paper Structure

This paper contains 5 sections, 8 equations, 3 figures, 1 table.

Table of Contents

  1. Introduction
  2. Methodology
  3. Data and results
  4. Discussion and Conclusions
  5. The parameters of 117 well-localized FRBs

Figures (3)

  • Figure 1: The probability distribution of each component of DM for FRB 20121102A (upper left), FRB 20190520B (upper right) and FRB 20200120E (lower-left). The vertical red-dashed lines are the 16th, 50th and 84th percentiles of the probability distribution of ${\rm DM_{host}}$, respectively. The vertical black-solid line is the value of ${\rm DM_{obs}}$, which has a negligible uncertainty. Lower-right: Histogram of $\ln{\rm DM_{host}}$ with the best-fitting Gaussian distribution superimposed.
  • Figure 2: The correlations between ${\rm DM_{host}}$ and the properties of host galaxies (redshift, stellar mass, SFR and galaxy age). The errorbar represents the $1\sigma$ uncertainty. The orange line represents the linear regression line calculated via the orthogonal distance regression method.
  • Figure 3: Distribution of Pearson's correlation coefficients from 10000 bootstrap samples. The 95% confidence interval is indicated by the dotted green lines, and the correlation coefficient from the original data is marked by the dashed red line.