Milky Way: Astronomers discover the origin of “the most luminous radio burst ever detected in our galaxy”
For the first time, astronomers have managed to track a fast radio burst in our galaxy: it comes from a strange type of stars called magnetars.
We are finally making progress in deciphering some of the most enigmatic signals in the Universe.
Scientists have managed to track down a very short and very bright burst of radio waves to a type of highly magnetized dead star, known as m agnetar (or magnetar) .
It is the first time that a fast radio burst – or FRB , for its acronym in English – has been located in a specific source.
These types of astrophysical phenomena were first detected in 2007. Since then they have been one of the hottest topics in astronomy.
The new discovery, explained in three studies published Thursday in the journal Nature , was made by two sets of independent radio telescopes in North America.
The observations, coinciding with those of other astronomical facilities both in space and on the ground, helped to characterize the event and strengthen its interpretation.
The source of the magnetar is designated by scientists with the complex formula SGR 1935 + 2154.
It’s about 30,000 light-years away , which is interesting because so far all previous detections of such bursts came from outside of our Milky Way galaxy.
The properties of the newly detected ones in our galaxy, however, are very similar to those of other fast bursts that occur beyond the Milky Way.
Luminous event
The event occurred on April 28 of this year. It lasted for about a millisecond , but it was extremely bright .
“We were able to determine that the scattered energy is comparable to the energies of extragalactic fast radio bursts. In just one millisecond, this magnetar emitted as much energy in radio waves as [our] Sun does in 30 seconds, ”explained Christopher Bochenek, who led the design and construction of the Stare2 radio receiver network, which spans California. and Utah (USA).
As early as 2007 magnetars were the main suspects in the origin of the FRBs.
Magnetars are u n type of star s Neutron : foreign objects and compact in which the matter has been compressed into a very small volume. It is a state that some normal stars can reduce to when they run out of fuel and collapse in on themselves.
Magnetars, as the name suggests, have strong magnetic fields , billions of times more than Earth’s magnetic field, for example.
The theory suggests that these objects can fire enormous amounts of energy that then collide with their surroundings, which in turn generates large emissions in radio and other wavelengths.
That’s one idea, but many other models have been proposed.
Other sources
“Given the distance from the source, this is the brightest radio burst ever detected in our own galaxy, ” said Daniele Michilli of the team that operates the Chime telescope in the Canadian province of British Columbia.
“The luminosity is still lower than that of fast radio bursts (coming from outside our Milky Way), but it shows that magnetars can release a large amount of radio energy with properties like FRBs, which implies that at least [some] FRBs probably come from magnetars. “
Bing Zhang, who works on China’s new giant radio telescope – the FAST (500-meter aperture spherical telescope) observatory, also called Tianyan – said other possible sources of FRB are being investigated.
For example, they could be colliding giant stars and neutron stars that experience a further collapse to become a black hole, an event called blitzar .
Such phenomena could explain the class of explosions that appear to be single events .
“But so far, we still don’t have anything to support those scenarios,” he told reporters. “If they exist, they must be very, very rare. Only a small fraction of fast radio bursts can be catastrophic. “
