Key takeaways
- Sgr 1935+2154, a magnetar in the milky way, emitted a powerful burst of radio waves on April 28, 2020, that may help solve the mystery of fast radio bursts (FRBs).
- This radio burst, lasting less than a millisecond, was accompanied by a bright x-ray emission, which is commonly seen in magnetar flares but not in extragalactic FRBs.
- Researchers believe this event supports the theory that frbs originate from magnetars, a type of neutron star with extremely strong magnetic fields.
- The radio burst was detected by various global observatories, including the chime telescope and the stare2 survey, providing strong evidence of its intensity.
- While this discovery is significant, further analysis and observations are needed to fully understand FRBs and confirm if magnetars are their sole source.
SGR 1935+2154, a magnetar in the Milky Way, could have just made a significant contribution to the long-standing puzzle of strong radio signals coming from deep space that have baffled astronomers for years.
The dead star, which is just 30,000 light-years distant, was observed by radio observatories all around the world on April 28, 2020. It seemed to flare with a single, millisecond-long burst of very intense radio waves, which would have been observable from another galaxy.
Furthermore, a very brilliant X-ray counterpart was detected by worldwide and space X-ray observatories.
Astronomers are working nonstop to analyze the vast amounts of data, but their work on this event is still extremely early. However, a lot of people appear to agree that it could finally identify the origin of rapid radio bursts (FRBs).
According to astronomer Shrinivas Kulkarni of Caltech, who was a part of the STARE2 survey team that also discovered the radio signal, “this sort of settles the origin of FRBs as coming from magnetars,” as stated to ScienceAlert.
One of the universe’s most intriguing mysteries is the nature of fast radio bursts. These are incredibly strong radio signals coming from galaxies millions of light-years out in deep space; some of them are capable of emitting energy equivalent to 500 million Suns. However, their duration is less than a millisecond, and the majority of them are non-repeating, making it extremely difficult to anticipate, track, and comprehend.
Supernovae and aliens have been proposed as possible explanations (which, unfortunately, is exceedingly doubtful). However, the theory that FRBs are generated by magnetars is one that has gained traction recently.
The extraordinarily dense core remains that remain after a large star supernovae are a particularly peculiar kind of neutron star. However, magnetars have magnetic fields that are approximately 1,000 times greater than those of regular neutron stars. We don’t really know how they got that way, but it has an intriguing effect on the star itself.
The magnetic field is so strong that it warps the form of the star while the inward gravity pull works to hold it together. According to Kulkarni, this results in a constant tension between the two forces, which periodically causes enormous starquakes and massive magnetar flares.
A flurry of equipment, including the Swift Burst Alert Telescope, the AGILE satellite, and the NICER ISS payload, spotted and observed SGR 1935+2154 on April 27, 2020. At first glance, it appeared rather normal, matching the behavior seen in other magnetars.
However, on April 28, an unusual discovery was made by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a telescope built to search the heavens for transient occurrences. The signal was so strong that the instrument was unable to fully measure it. The Astronomer’s Telegram published a report on the finding.
However, Caltech graduate student Christopher Bochenek created the STARE2 survey, which is specifically intended for the identification of nearby FRBs. It is made up of three radio antennas with dipoles that are hundreds of kilometers apart. This allows for signal triangulation in addition to the ability to exclude human-produced local signals.
It picked up the signal with a fluence of more than a million Jansky milliseconds, clear and crisp. Extragalactic fast radio bursts are often received at a few tens of jansky milliseconds. The SGR 1935+2154 would be on the low end of FRB power once distance has been adjusted, but Kulkarni indicated it matches the profile.
“If the same signal came from a nearby galaxy, like one of the nearby typical FRB galaxies, it would look like a FRB to us,” he stated to ScienceAlert. “Something like this has never been seen before.”
However, we also observed the X-ray counterpart, which is something we have never seen in an extragalactic fast radio background. Naturally, these occur often in magnetar eruptions. Actually, X-ray and gamma radiation emission from magnetars is significantly more common than radio waves.
According to astronomer Sandro Mereghetti of the National Institute for Astrophysics in Italy and a research scientist working with ESA’s INTEGRAL satellite, the X-ray counterpart to the SGR 1935+2154 explosion was neither exceptionally intense nor uncommon. However, it could suggest that there’s a lot more to FRBs than we can currently detect.
According to Mereghetti, “this is a very intriguing result and supports the association between FRBs and magnetars,” ScienceAlert said.
“The FRB found so far are extragalactic in nature. They have never been found at gamma or X-ray wavelengths. For an extragalactic source, an X-ray burst with the brightness of SGR1935 would be invisible.”
Still, there was no denying that radio signal. Furthermore, Kulkarni asserts that a magnetar may very well cause much greater outbursts. For a magnetar, the burst of SGR 1935+2154 did not need much energy, and the star could easily withstand a burst a thousand times greater.
It’s definitely exciting stuff. However, it’s critical to remember that we are still in the early stages. Using some of the most potent instruments available to humanity, astronomers are continuing performing follow-up observations of the star.
Furthermore, they have not yet analyzed the burst’s spectrum to see if it resembles the spectra of extragalactic rapid radio bursts in any way. If not, we could find ourselves starting over.
Of course, this doesn’t mean that SGR 1935+2154 is the only source of rapid radio bursts, even if it does prove to be a magnetar origin. Certain signals exhibit very erratic behavior and repeat at random. It was recently discovered that one source repeated every 16 days.
Whatever SGR 1935+2154 reveals, it’s a very exciting step forward, and we are still a long way from understanding the complex mystery these amazing signals represent.
