© A. Moroianu, AstroFlash

Fast radio bursts (FRBs) are extremely luminous, millisecond-duration extragalactic radio transients, first discovered in 2007. Despite thousands being detected, their origins and emission mechanisms are still unknown. Most FRBs are seen only once, but a few repeat. This raises a fundamental question: **do all FRBs share a common progenitor, or do multiple source classes exist?** One way to address this is by zooming in on the local environments of FRB sources.

In a new study published by Moroianu et al. (https://scixplorer.org/abs/2025arXiv250905174M/abstract), we used the European VLBI Network (EVN) to localize a repeating FRB, 20190417A, with milliarcsecond precision. We confirmed that the FRB is spatially coincident with a compact persistent radio source (PRS) located in a metal-poor, star-forming dwarf galaxy. This makes FRB 20190417A only the fourth confirmed FRB–PRS association.

With this addition, FRB–PRS systems are emerging as a distinct subclass with shared characteristics: unusually large and often variable Faraday rotation, high dispersion measures indicating dense local and extreme environments, and host galaxies that are chemically primitive and actively forming stars. Together, these properties point to FRB progenitors linked to the remnants of massive, rapidly rotating stars embedded in extreme magneto-ionic environments. While the origin of the PRSs themselves is still uncertain, our findings suggest that their presence may reflect either an environmental selection effect, or a distinct engine for FRB emission.