One of the two papers published Wednesday looks at the polarization of the photons in the burst itself, finding that the polarization angle changes rapidly during the 2.5 milliseconds that FRB 20221022A lasted. The 130-degree rotation that took place follows an S-shaped pattern, which has already been observed in about half of the pulsars we've observed: neutron stars that spin rapidly and sweep a bright beam across the line of sight with Earth, usually several times per second.
The implication of this finding is that the source of the FRB is also likely to be on a compact, rapidly rotating object. Or at least this FRB. At this time, this is the only FRB we know of that exhibits this type of behavior. While not all pulsars exhibit this rotation pattern, half do, and we certainly observed plenty of FRBs. We should have noticed others like this if they were happening at a significant rate.
Spread out
The second paper performs a much more complicated analysis, looking for clues to interactions between the FRB and the interstellar medium found in galaxies. This will have two effects. One of them, caused by the scattering of interstellar material, will spread the outburst in a frequency-dependent manner in time. Scattering can also cause a random brightening/dimming of different parts of the spectrum, called scintillation, and somewhat analogous to the twinkling of stars caused by our atmosphere.
In this case, the FRB's photons have had three encounters with matter that could cause these effects: the sparse interstellar material of the source galaxy, the equally sparse interstellar material in our own Milky Way, and the even sparser intergalactic material in between. the two. Because the source galaxy for FRB 20221022A is relatively close to ours, the intergalactic medium can be ignored, leaving the detection with two major sources of scattering.
