Speaker
Description
Fast radio bursts (FRBs) are millisecond-duration radio transients of extragalactic origin whose progenitors and emission mechanism(s) remain mysterious. Of the ~4000 FRBs discovered to date, only ~100 repeat, raising the question of whether repeating and apparently non-repeating FRBs arise from the same underlying population.
I present recent milliarcsecond localisations of FRBs that reveal the diversity of their environments and provide new insights into their formation channels. The repeating FRB 20190417A, localised with the European VLBI Network, coincides with a compact persistent radio source (PRS; a long-lived luminous radio emitter) in a low-metallicity, star-forming dwarf galaxy. The properties of this system suggest that PRSs signal FRB sources embedded in highly magnetised, dense, and metal-poor environments. In contrast, the repeating FRB 20181119A was traced back to a host galaxy with an older stellar population and shows no evidence for a luminous PRS. This dichotomy points to multiple formation channels for repeating FRBs, including dynamical pathways in more mature stellar systems.
Looking ahead, FRBs detected in the side lobes of the CHIME telescope (i.e., > 5 degrees away from the telescope's pointing direction) provide promising new targets for precise localisation. These events are on average ~500$\times$ brighter and are therefore ~20 times closer than typical FRBs. With the CHIME/FRB Outriggers achieving ~50 milliarcsecond localisation precision, such nearby sources will enable detailed studies of the local environments of non-repeating FRBs: a crucial step towards determining whether repeaters and non-repeaters occupy similar environments.
| Talk category | NOVA Network 3 |
|---|---|
| PhD relevance | 2nd |
