Calibrating the DMIGM–z Relation Using Host Galaxy Properties of Fast Radio Bursts

Abstract

Fast radio bursts (FRBs) are extragalactic radio transients that offer valuable insight into the intergalactic medium (IGM). However, the dispersion measure (DM) contributed by the IGM (DM _IGM ) is degenerate with that from the host galaxy (DM _host ), necessitating calibration of the DM _IGM − z relation for cosmological applications. As DM _host is expected to correlate with host galaxy properties, it is feasible to estimate DM _host from observable host characteristics. In this study, we conduct spectral energy distribution and Sérsic model fittings to derive the parameters of FRB host galaxies. Then, we examine the correlations between the excess dispersion measure (DM _exc ) and host galaxy parameters, including star formation rate, stellar mass, specific star formation rate (sSFR), inclination angle, and projected area. A tight correlation between DM _exc and sSFR is found. This correlation is utilized to estimate DM _host of FRBs, providing a method to calibrate the DM _IGM – z relation. This approach leads to a notable improvement in calibration performance.

Keywords

• Radio bursts
• Star formation
• Interstellar medium
• Radio transient sources
• Galaxies