Now and again, astronomers will detect an odd type of radio sign. So highly effective it may well outshine a galaxy, however lasting solely milliseconds. They’re referred to as quick radio bursts (FRBs). Once they have been first found a few many years in the past, we had no thought what would possibly trigger them. We weren’t even certain in the event that they have been astronomical in origin. FRB’s have been so localized and so short-lived, it was tough to collect information on them. However with wide-field radio telescopes akin to CHIME we will now observe FRBs repeatedly and have a reasonably good thought of their supply: magnetars.
Magnetars are neutron stars with immensely highly effective magnetic fields. Now that we will localize FRBs, we’ve got been capable of match a few of them to the area of a neutron star. Whereas most FRBs happen in distant galaxies, in 2020 we noticed one inside the Milky Method. The magnetar supply additionally occurred to be a pulsar, and astronomers have been capable of present that the FRB [correlated with a glitch in the pulsar’s rotation,](https://briankoberlein.com/weblog/power-of-magnetism/) thus confirming the supply. So we’re pretty sure that FRBs are brought on by neutron stars, however we’re nonetheless unsure in regards to the precise mechanism.
One well-liked thought is that quick radio bursts are brought on by magnetic realignments. That is what drives flares on the Solar. Over time, the Solar’s magnetic discipline traces can get tangled up till they snap into realignment, releasing power. If the same impact happens on magnetars, the ensuing snap can be a lot quicker and extra highly effective. One issue with this concept is that FRBs are so short-lived that they’re virtually too quick for magnetic discipline traces to realign. So astronomers hold on the lookout for new concepts, and one not too long ago proposed argues that they’re brought on by impression occasions.
Collisions have lengthy been referred to as the supply of high-energy occasions. For instance, some supernovae are brought on by the collisions of neutron stars. We additionally know that comets and asteroids sometimes impression the Solar, so we’d anticipate related impacts to happen on neutron stars. On this new work, the authors suggest that FRBs are brought about when an interstellar physique collides with a neutron star. The impression would set off a robust electromagnetic burst. To help their argument, the authors appeared on the distribution of FRBs organized by length. The timing of FRBs follows a distribution much like the distribution of photo voltaic system our bodies. Not solely that, the length of an FRB appears to match the hypothetical length of an impression occasion primarily based on an object’s measurement.
Whereas the info does appear to help the thought of impact-based FRBs, the examine doesn’t remedy all of the mysteries surrounding these highly effective bursts. We all know, for instance, that some FRBs are repeaters, that means they happen a number of instances from the identical supply. Some research have proven that repeating FRBs are quasi-periodic, which might be tough to elucidate by way of random collisions. It’s potential that repeating and non-repeating FRBs are brought on by completely different mechanisms, although the info continues to be inconclusive on that time.
Reference: Pham, Dang, et al. “Quick Radio Bursts and Interstellar Objects.” arXiv preprint arXiv:2411.09135 (2024).
