Fast Radio Bursts Associated with Persistent Radio Sources Prefer Hydrogen-poor Superluminous Supernova Host Environments

A subset of repeating fast radio bursts (FRBs) is associated with compact persistent radio sources (PRSs). The FRB-PRS hosts differ dramatically from the general FRB host population: they do not follow the distribution of localized non-PRS FRB hosts, nor the SFR-weighted or mass-weighted mock host distributions expected for the general star-forming galaxy population, instead occupying the extreme low-mass, high-sSFR, and low-metallicity end of host-galaxy parameter space. We compare these hosts with well-defined samples of hydrogen-poor superluminous supernovae (SLSNe-I), hydrogen-rich superluminous supernovae (SLSNe-II), and Type II core-collapse supernovae (CCSNe). Using cumulative distribution functions and statistical tests, we find that FRB-PRSs tend to reside in dwarf galaxies with high specific star formation rates and low gas-phase metallicities, even relative to galaxies of similar stellar mass. Their hosts are most similar to those of SLSNe-I, but differ significantly from CCSN hosts, with SLSN-II hosts lying between these populations. These results suggest that FRB-PRSs do not simply trace star formation activity or the general FRB host population, but instead favor SLSN-I-like environments. This preference is consistent with young magnetars formed through low-metallicity massive-star channels, for which SLSN-I-like ejecta imply a characteristic free--free transparency time of 29 yr at 600 MHz.