Refined Constraints on the Hubble Constant from Localized FRBs with Assessment of Systematic Effects

TL;DR

This study uses 95 localized fast radio bursts to measure the Hubble constant with high precision, addressing systematic uncertainties to improve the reliability of FRBs as cosmological probes.

Contribution

It provides refined constraints on H_0 from FRBs and systematically assesses modeling uncertainties affecting these measurements.

Findings

Measured H_0 as 71.28^{+1.90}_{-2.08} km/s/Mpc with less than 2.8 ext{%} statistical uncertainty.

Identified key sources of systematic errors including Galactic electron density models and outliers.

Discussed mitigation strategies for systematic uncertainties in FRB-based cosmology.

Abstract

The dispersion measure-redshift relation of fast radio bursts (FRBs) provides a valuable cosmological probe for constraining the Hubble constant, offering an independent measurement that could help resolve the ongoing Hubble tension. In this paper, we begin with a sample of 117 localized FRBs and use 95 of them to constrain $H_0$ to $71.28^{+1.90}_{-2.08}$ km s$^{-1}$ Mpc$^{-1}$ within the standard Lambda Cold Dark Matter ($\Lambda$CDM) model. The resulting statistical uncertainty is below 2.8\%, improving previous FRB-based measurements and highlighting the promise of larger future samples. Beyond statistical improvements, we note that different parameter choices have been adopted in previous studies and some results show discrepancies in $H_0$. To address this issue, we perform a systematic assessment of modeling uncertainties that can affect the inferred value of $H_0$, including Galactic electron density models, the contribution of the Galactic halo, outliers such as FRB~20190520B located in extreme environments, and the other parameter selections. We also discuss possible approaches to mitigate these sources of uncertainty, emphasizing both the challenges and prospects of using FRBs as reliable cosmological tools.