Science Writing, Feb 23 (Latest) .- They last thousandths of a second and can arise from any point in the sky but each one sends as much energy as that emitted by the Sun in a single day: they are the rapid radio bursts or FRB, some mysterious Flashes discovered in 2007 that since then have been causing astronomers to go crazy.
Until now, all the bursts captured by radio telescopes came from remote galaxies, located billions of light years away, but today, two articles published in Nature and Nature Astronomy report, for the first time, FRBs that come from a unexpected place: a cluster of old stars that, moreover, is relatively close to us, in the spiral galaxy M 81.
The research, directed by Franz Kirsten, from the University of Chalmers (Sweden), and by Kenzie Nimmo, from the University of Amsterdam (The Netherlands), has had the participation of the Spanish astrophysicist Benito Marcote (JIVE, the Netherlands), second author of the article in Nature.
Fast radio bursts are beams of light that are extremely difficult to pick up because it is impossible to know when and where they are going to come from.
Since the first one was detected, hundreds of these objects have been observed, but the precise location of only a couple of them, FRB 121102 and FRB 180916, which recur periodically, is known; the rest were seen only once.
But in January 2020, astronomers discovered a completely different burst from the previous ones. It came from the constellation Ursa Major.
To determine exactly which region of the galaxy it came from, the scientists synchronized the work of a dozen antennas distributed throughout the world belonging to the European VLBI Network, achieving a resolution “equivalent to that of distinguishing a person walking through the surface of the Moon”, the Cantabrian researcher Benito Marcote explains to Latest.
The observations determined that these bursts came from the outskirts of the nearby spiral galaxy Messier 81 (M 81), about 12 million light-years away, the closest point to Earth from which FRBs have ever emerged.
But there’s more: Until now, all the radio bursts studied have come from places where stars are young and massive, and where supernova explosions occur.
But the location of these FRBs exactly matched a globular cluster of very old stars. Again, quite the opposite of what has been seen so far.
“It is amazing to find these fast radio bursts inside a globular cluster. This is a place in the Universe where you only find old stars. Whereas until now, we have only found fast radio bursts in places where the stars are much younger. This had to be something else,” said Kenzie Nimmo, lead author of the Nature Astronomy paper.
The authors believe that a possible explanation would be that these bursts were associated with magnetars, which are the remains that stars can leave behind after exploding as supernovae.