The most accurate measurement ever made of a fast radio burst reveals a new pattern in these signals from space
In recent years one of the things that has most fascinated astronomers are fast radio bursts. These are signals that generally come from very far distances in space and are captured by radio telescopes. They often also follow patterns of repetition that help to better understand what they are about. Now a new study has analyzed the most accurate pattern of these signals: a matter of several microseconds.
The sudden and repetitive pulses of fast radio bursts are captured by the world’s largest radio telescopes. They barely last a few milliseconds, so it is essential to be aware and avoid any type of interference (such as a microwave). Although this allows us to deduce in part their origin and what causes them, a more exhaustive analysis helps even more.
That is the precision with which some astronomers have managed to analyze a fast radio burst, according to the study they have published. in nature. Within the millisecond bursts, they have managed to analyze with more precision time periods as short as 3 or 4 microseconds. Consequently, they have found a variable brightness pattern or structure in the signal, thus revealing clues about the physics of this emission.
The signal was captured by the European Very Long Base Interferometry Network (EVN) made up of radio astronomy institutes from several European countries. The analyzed signal is an old acquaintance here, it is FRB 180916 and as we saw at the time, repeats every 16 days.
According to the researchers, the fact that there is brief variations in brightness at such a small scale it means that the size of the emission region of the fast radio burst is very limited. In other words, the object that emits it must be very small, having been able to find variations on such a small scale. According to his calculations, it has to be something about a kilometer in scale.
Why is this relevant? Because of how incredible it is to be able to reduce an emission to an area of just one kilometer. Yes, a kilometer may seem like a lot, but not in an environment like space. Even less if we take into account that FRB 180916 is 457 light years from us. To put it in context, 1 light year equals about 9,460,730,000,000 kilometers. Anyway sometimes they are closer to us, like in our galaxy or even in Proxima Centauri.
Likewise, at scales of less than 100 microseconds, scientists can begin to observe variations in the angle of polarization position of the light. This property allows astronomers to better know how close the radio emission is to its source which in turn allows them to better understand the rotation of the object that produces the fast radio burst.
With this theory, scientists determine that what is really causing FRB 180916 is a binary system of a neutron star and a massive star. Both are believed to share a 16-day orbital cycle. When they are relatively close, the interactions between the two amplify the fast radio bursts and that is when they reach us. Although of course, this in theory happened more than 457 million years ago and it is now that it has come to us.
More information | Nature