Scientists got a strange sense of déjà vu when they took a closer look at a mysterious series of bright flashes in a galaxy just 12 million light-years away.
The flashes, known as a frequent fast radio burst (FRB), look surprisingly similar to flashes in the Crab Nebula. The Crab Nebula is a remnant of an ancient starburst, or Supernova, observed by humans in 1054 AD, and recorded by several distinct cultures. The colorful remains showed bright, brilliant flashes very similar to the newly discovered FRBs, which occurred in the galaxy M81, the researchers said.
“Some of the signals we measured are very short and strong, just like some of the signals from the Cancer pulsar,” Kinsey Nemo, Ph.D. Student in astronomy at the Netherlands Institute for Radio Astronomy and the University of Amsterdam in the Netherlands, He said in a statement.
The explosion was in what is now the Crab Nebula registered on July 4, 1054 by Chinese astronomers, who saw a new or “guest” star over the southern horn of Taurus. Astronomers recorded that the “Guest” shone in the sky for 23 days and was 6 times brighter than Venus. It remained visible for about two years after the explosion, and was also recorded by Arab and Japanese astronomers.
The rest was better visible with a telescope, meaning that the remaining nebula was first observed only in 1731 by British astronomer John Bevis. French astronomer Charles Messier He observed it independently 27 years later and added it to his now-popular catalog of Messier objects, describing the nebula as Messier 1 or M1.
And it wasn’t until the 1960s that astronomers noticed an oscillating radio source that coincided with the location of the Crab Nebula, and eventually determined that the signal came from pulsara type of neutron star (itself a super-dense stellar body left behind by a supernova) with a strong magnetic field.
But despite the known cause of the Crab Nebula’s eruptions and their similarities to those seen in M81, astronomers aren’t yet sure what’s happening in M81. These FRBs were first observed in January 2020, coming from the direction of the constellation Ursa Major, the Great Dipper.
So far, FRBs have been found mostly in young star-studded galaxies, but the M81 sightings are an exception, since a network of dozens of radio dishes very clearly identified the source of the signal for an ancient group of stars known as a globular cluster. .
One candidate to explain FRBs is that these bright flashes come from magnetism The most powerful magnet in the universe and another type of supernova remnant. This explanation makes sense in places where young stars are common, the researchers said, but it’s more challenging when it comes to M81.
“We expect magnetic stars to be bright and new, certainly not surrounded by old stars,” Jason Hessels, of the University of Amsterdam and Astron, said in the statement. “If what we’re looking at here is really a magnetar, it couldn’t have formed from the explosion of a young star. There has to be another way.”
One possible explanation may be that the file white dwarf (Cooling core of a large burning star) It draws gas from an unlucky neighboring star. Researchers believe that over time, the extra mass may have caused the white dwarf to collapse into a magnetar.
Finally, although scientists aren’t sure what the signal is or why it’s similar to that emanating from the Crab Nebula, they suspect the answer is something unusual — whether it’s an unusual magnetar, an unusual pulsar, or another celestial phenomenon.
The research was published in two papers on Wednesday (February 23): one in natural astronomy Led by Nemo and the other in nature It was led by Franz Kirsten, of Chalmers University of Technology and the Netherlands Institute for Radio Astronomy.
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