2026MNRAS.545f1997U

Fast radio bursts (FRBs) are luminous, dispersed pulses of extragalactic origin. The physics of the emission mechanism, the progenitor environment, and their origin are unclear. Some repeating FRBs exhibit a frequency-dependent decrease in linear polarization fraction. This has been attributed to multipath propagation in a surrounding complex magneto-ionic environment. In this framework, the depolarization magnitude can be quantified using the parameter $\sigma ^{\prime }_{\rm RM}$, which can be used to model the magneto-ionic complexity of the medium. In addition to depolarization, some repeating sources (specifically, those with complex magneto-ionic environments) have been identified to have co-located persistent radio sources (PRS). Searches for depolarization of non-repeating sources are challenging due to the limited bandwidth of most FRB detection systems. However, even with a limited bandwidth, such depolarization can be identified if it lies within the $\sigma ^{\prime }_{\rm RM}$ sensitivity window of the telescope. In this paper, we present a search for depolarization in 12 one-off FRBs detected by the Australian SKA Pathfinder. We report on a strongly depolarized (apparently) non-repeating FRB detected by ASKAP (FRB 20230526A). The source shows a decrease in linear polarization fraction from $\sim$60 per cent at 1440 MHz to $\sim$20 per cent at 1110 MHz. We also report constraints on the presence of a PRS coincident with FRB 20230526A using observations obtained with the Australia Telescope Compact Array. We use this to study the relationship between $\sigma ^{\prime }_{\rm RM}$ and PRS luminosity. Our investigation supports a scenario in which repeaters and non-repeaters share a common origin and where non-repeaters represent an older population relative to repeating FRB sources.