ASTRO In the literature: open

How do FRB sources arise in old stellar populations?

In plain words

Some bursts come from a globular cluster (a ball of stars about $1e10\,\mathrm{years}$ old) or from galaxies that stopped forming stars long ago, where newborn magnetars should be absent.

Precise statement

FRB 20200120E lies in a globular cluster of M81 and other FRBs localize to quiescent galaxies. Determine the formation channel of the active sources there (accretion-induced collapse of white dwarfs, white-dwarf or neutron-star mergers, accreting compact binaries) and its rate per unit stellar mass. Answer: a channel whose rate matches the observed fraction of FRBs in old hosts.

What would settle it

Precise localizations of a statistical sample of FRBs in old environments, with the rate per stellar mass compared to channel predictions.

Status in the literature

Unverified note

2025: the repeating source FRB 20240209A was localized to the outskirts of a quiescent elliptical galaxy.