A radio signal coming from outside the Earth that lasted a few seconds but was detected “closer than ever”.
Thirty thousand years ago, a dead star on the other side of the Milky Way emitted a powerful mixture of radio and X-ray energy. On April 28, 2020, that “burp” swept across the Earth, setting off alarms at observatories around the world. .
The signal came and went in half a second, but that’s all the scientists needed to confirm that they had detected something remarkable: the first “fast radio burst” (FRB) that emanated from a known star within the Milky Way, according to a study published on July 27 in The Astrophysical Journal Letters.
Bewildered scientists
Since their discovery in 2007, FRBs have baffled scientists. Bursts of powerful radio waves last only a few milliseconds at most, but generate more energy in that time than Earth’s Sun does in a century. Scientists have yet to pin down what causes these explosions, but they have proposed everything from black hole collisions to the pulse of alien ships as possible explanations. Until now, every known FRB originated in another galaxy, hundreds of millions of light years away.
Courtesy: space.com
However, this FRB is different. Observations from the telescope suggest that the outburst came from a known neutron star, the compact, fast-spinning core of a dead star, possessing the mass of the sun in a city-sized ball, about 30,000 light-years from the planet. Earth in the constellation Vulpecula.
The stellar remnant fits into an even stranger class of star called magnetar, named for its incredibly powerful magnetic field, which is capable of spitting out intense amounts of energy long after the star itself has died. It now appears that magnetars are almost certainly the source of at least some of the universe’s many mysterious FRBs, the study authors wrote.
Sandro Mereghetti, of the National Institute for Astrophysics and lead author of the study, said in a statement:
“We have never before seen a burst of radio waves, similar to a fast radio burst, from a magnetar. This is the first observation connection between magnetars and fast radio bursts ”.
Simultaneous detections
The magnetar, named SGR 1935 + 2154, was discovered in 2014 when scientists saw it emitting powerful bursts of gamma rays and X-rays at random intervals. After calming down for a while, the dead star was awakened by a powerful X-ray blast in late April. Sandro and his colleagues detected this explosion with the integral satellite of the European Space Agency (ESA), designed to capture the most energetic phenomena in the universe.
Courtesy: space.com
At the same time, a radio telescope in the mountains of British Columbia, Canada, detected an explosion of radio waves coming from the same source. Radio telescopes in California and Utah confirmed the FRB the next day.
The researchers wrote that a simultaneous burst of radio waves and X-rays had never before been detected in a magnetar, strongly pointing to these stellar remnants as plausible sources of FRB.
Crucially, the ESA scientist, Erik Kuulkers He added, this finding was only possible because multiple telescopes on Earth and in orbit were able to catch the blast simultaneously, and at many wavelengths across the electromagnetic spectrum. Greater collaboration between institutions is needed to “focus even more on the origin of these mysterious phenomena,” Kuulkers said.
The scientific study has been published in The Astrophysical Journal Letters.
Source: Live Science / ESA
