Redshift dependence of FRB host dispersion measures across cosmic epochs

TL;DR

This study investigates how the dispersion measures of FRB host galaxies depend on redshift, using a power-law model, to better understand galaxy evolution and improve cosmological models.

Contribution

It introduces a model fitting approach to constrain the redshift dependence of FRB host dispersion measures using current observational data.

Findings

Preferred $oldsymbol{\alpha}$ between 0 and 1 depending on model assumptions

Current data constrains $|oldsymbol{\alpha}| oldsymbol{\lesssim 2}$ at 68% confidence

Results inform galaxy formation theories and large-scale simulations

Abstract

We constrain the redshift dependence of (rest frame) host galaxy dispersion measures of localized Fast Radio Bursts (FRBs) by assuming it to vary as a simple power law ($\propto (1+z)^{\alpha}$). We simultaneously fit $\alpha$ as well as the host dispersion measure to the data of FRBs with known redshifts. We find that \color{black} $\alpha$ between 0 to 1 is preferred depending upon our modelling choices. Current data can constrain $|\alpha|\lesssim 2$ at a 68 percent confidence interval \color{black}. Such constraints have implications for our understanding of galaxy formation and can be used to inform galaxy and large scale simulations.