2025ApJ...984L..40Z

We introduce a novel method to constrain the Hubble constant (H₀) by combining fast radio bursts (FRBs) and their persistent radio sources (PRSs) through the observationally validated Yang relation, L_ν ∝ ∣RM∣, which links PRS luminosity to the rotation measure of the associated FRB. Using a mock sample of PRSs, we demonstrate that the Yang relation can help to unravel the degeneracies among H₀, baryon density parameter Ω_b, and baryon fraction in the intergalactic medium f_IGM in the traditional approach of using dispersion measure only to perform cosmological analyses. Our method employs a two-stage Markov Chain Monte Carlo analysis to constrain H₀. Using the available data of six observed PRS systems, we obtain a preliminary constraint of H₀ = 75 ± 30 km s^–1 Mpc^–1. We briefly discuss possible refinements of the method by reducing residual degeneracies and systematic uncertainties using future data and physical modeling. Our results indicate that the Yang relation can potentially become a new probe for performing FRB cosmology.