Fast radio bursts are brief and brilliant explosions of radio waves emitted by extremely compact objects such as neutron stars and possibly black holes. These fleeting fireworks last for just a thousandth of a second and can carry an enormous amount of energy—enough to briefly outshine entire galaxies.
Astronomers at MIT have pinned down the origins of at least one fast radio burst using a novel technique that could do the same for other FRBs. The team focused on FRB 20221022A—a previously discovered fast radio burst that was detected from a galaxy about 200 million light-years away.
To determine the precise location of the radio signal, the scientists analyzed its “scintillation,” similar to how stars twinkle in the night sky. They reasoned that if they could estimate the degree to which an FRB scintillates, they might determine the relative size of the region from where the FRB originated.
The team looked at FRB 20221022A and found that its light was highly polarized, with a smooth S-shaped curve in the angle of polarization. This pattern is interpreted as evidence that the FRB emission site is rotating—a characteristic previously observed in pulsars, which are highly magnetized, rotating neutron stars.
By analyzing data from CHIME, the researchers confirmed that there was gas somewhere between the telescope and FRB that was bending and filtering the radio waves. They then determined where this gas could be located and confirmed that it was within the host galaxy of the FRB.
This allowed the team to zoom in on the FRB site and determine that the burst originated from an extremely small region, estimated to be about 10,000 kilometers wide. The results rule out the possibility that FRB 20221022A emerged from the outskirts of a compact object, instead proving for the first time that fast radio bursts can originate from very close to a neutron star in highly chaotic magnetic environments.
The study’s findings provide new insights into the physics driving fast radio bursts and demonstrate the potential of scintillation technique to help disentangle the various physics that drive these events.
Source: https://phys.org/news/2024-12-scientists-pin-fast-radio.html