A Milky Way magnetar named SGR 1935 + 2154 may have helped solve – at least in part – the mystery of the powerful fast radio bursts (FRBs) that have puzzled astronomers for years.
On April 28, 2020, a stellar remnant located at around 30,000 light-years from Earth in the Vulpecula constellation, was recorded by various radio observatories around the world by emitting a brief but extremely bright burst of radio waves. X-ray observatories around the world noticed the same thing. While astronomers are still analyzing the data, many think that this particular outburst could finally help explain, in part, the source of the mysterious Fast Radio Bursts (FRB). “This would locate the origin of the FRBs in the magnetars,” said astronomer Shrinivas Kulkarni of Caltech and a member of STARE2, one of the teams that spotted the radio signal.
FRBs are one of the most fascinating mysteries in the entire cosmos. they are extremely powerful radio signals coming from deep space, from galaxies millions of light-years away, with the power and energy of 500 million Suns. Still, they last a blink of an eye – mere milliseconds – and most don’t repeat again, making them very difficult to predict, track, and, therefore, understand.
Potential explanations range from supernovae to alien civilizations. However, the possibility that has been gaining more strength over time is that most FRBs are generated by magnetars (a type of neutron star powered by an extremely strong magnetic field, the main feature of which is the ejection of huge amounts of high energy in the form of X-rays and gamma rays). Observation On April 27, SGR 1935 + 2154 was detected and observed by various instruments. The following day, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope, designed to scan the skies for transient events, made an unprecedented detection – a signal so powerful that the system couldn’t quantify it.
Because of this, the detection was reported in the Astronomer’s Telegram. However, the STARE2 Survey, a project created by Christopher Bochenek, a Caltech graduate student, entered the ring to help resolve the matter. Thanks to three radio dipole antennas separated by hundreds of kilometers between them, scientists were able to spot the FRBs loud and clear, with a fluidity of about one million milliseconds jansky (jansky: a unit of flux density, equivalent to 10ˆ26 watts per square meter and by hertz).
“Typically, we receive extragalactic FRBs within a few tens of jansky milliseconds,” Kulkarni explained to Science Alert. But in addition to the unusual intensity, which far exceeds that of any extragalactic FRB detected so far, the researchers also recorded X-rays coming from the same direction. The latter are very common in magnetars.
“If the same signal came from a nearby galaxy, like one of the nearby typical FRB galaxies, it would look like an FRB to us,” he told ScienceAlert. “Something like this has never been seen before.”
The researchers have explained that the X-ray counterpart is something that has never been seen in an extragalactic FRB. Nonetheless, these are common in magnetar outbursts. As revealed by Science Alert, it is far more normal for magnetars to emit X-ray and gamma radiation than radio waves.
Sandro Mereghetti of the National Institute for Astrophysics in Italy explained that the X-ray counterpart to the SGR 1935+2154 burst was not particularly strong or unusual, but it could suggest there much more to FRBs than what we are capable of detecting to date.
“This is a very intriguing result and supports the association between FRBs and magnetars,” Mereghetti told ScienceAlert.
“The FRB identified up to now are extragalactic. They have never been detected at X/gamma rays. An X-ray burst with luminosity like that of SGR1935 would be undetectable for an extragalactic source.”