Fast Radio Bursts

Fast radio bursts (FRBs) are bright pulses of radio emission that last only a tiny fraction of a second. Most are detected by radio telescopes exclusively between 0.1 - 8 GigaHertz radio frequencies. The origin of FRBs is not yet known; as of this writing, they are a frontier of discovery in astronomy. Most FRBs occur as a single burst, but a few have been found to repeat, and have been associated with external galaxies.

One FRB was recently found to originate in a "magnetar" in our own Milky Way galaxy. A magnetar is a neutron star (the dense remnant core of a massive star) with an extremely powerful magnetic field. Another was found to be associated with a gamma-ray burst (GRB) in another galaxy. Both these associations indicate that FRBs are probably associated with the remnants of massive stars that have exploded as supernovae.

FRB 20210401A

The FRB 20210401A was detected by ASKAP, a 36-antenna radio telescope array between 2021 April 1 and April 7 UTC. ASKAP detected 11 bursts from the FRB 20201124A source.

The light curve below shows a simple, single burst of radio flux, with zero flux on either side.

The spectrum below shows the host galaxy coincident with the sky position of FRB 20210401A. This is a spectrum of a typical star-forming galaxy, showing bright emission lines of hydrogen, and weaker lines of oxygen, silicon and nitrogen. These lines are redshifted by the expansion of space (the Big Bang) according to the distance of the galaxy, 1.3 billion light years from Earth, corresponding to this redshift of 0.0979.

Credit: W. Fong, P. Kumar, and the CRAFT collaboration.
Link to paper