A fast radio burst associated with a Galactic magnetar.

Since their discovery in 2007, much effort has been devoted to uncovering the sources of the extragalactic, millisecond-duration fast radio bursts (FRBs). A class of neutron stars known as magnetars is a leading candidate source of FRBs. Magnetars have surface magnetic fields in excess of 10 gauss, the decay of which powers a range of high-energy phenomena.

A fast radio burst localized to a massive galaxy.

Intense, millisecond-duration bursts of radio waves (named fast radio bursts) have been detected from beyond the Milky Way. Their dispersion measures-which are greater than would be expected if they had propagated only through the interstellar medium of the Milky Way-indicate extragalactic origins and imply contributions from the intergalactic medium and perhaps from other galaxies. Although several theories exist regarding the sources of these fast radio bursts, their intensities, durations and temporal structures suggest coherent emission from highly magnetized plasma.