The strange galactic radio signal has baffled astronomers

Over the course of 2020, astronomers in Australia have detected a mysterious band of radio waves coming from somewhere near the center of the planet. galaxy. But when the team directed and trained a more sensitive tool at the source, they only detected it once before it disappeared, and it behaved differently than it did before. The reference is described in an article published in Astrophysical Journal.

The strangest characteristic of this new signal is that it has very high polarization. This means that its light oscillates in only one direction, but that direction rotates over time,” said Ziteng Wang, an astrophysicist at the University of Sydney and lead author of the new study, in release from the University. In other words, the radio waves were going to Earth intermittently, without any kind of rhythm or impulse. And since they were spotted, the lane has gotten cold.

The signal was detected using a system on a square kilometer array in Australia’s Pathfinder (Aussie square kilometer array, or ASKAP), a radio telescope based in extremely remote Western Australia. The mysterious object that produced the signal, ASKAP J173608.2-321635, is named after the telescope that found it and its coordinates in the sky.

“This object was unique in that it began invisible, became shiny, dull, and then reappeared. This behavior was unusual,” said Tara Murphy, an astrophysicist at the University of Sydney and co-author of the research, in the same statement.

When the radio source was turned off, the team checked the visible light spectrum and found nothing. They also used a radio telescope Different, which also found nothing. But later, using the MeerKAT radio telescope in South Africa, the team finally saw the object again, but it was gone within a day. Researchers have not seen him since.

As for why the source stopped emitting, it could be something related to instability in the magnetic field. David Kaplan, co-author of the research paper and an astrophysicist at the University of Wisconsin-Milwaukee, said in an email to Gizmodo. “It happens with our sun, with magnetars and other types of bodies. So, it doesn’t stop much, because it only broadcasts intermittently (most of the time it’s off).O).

The researchers have some ideas about where the radio came from, but they aren’t sure which one. The radio wave pattern is similar to a class of objects called Radio Transients of the Galactic Center, although there are some differences as well. Galactic center radio transients are not something specific, but rather a group of radio-emitting objects around the center of the Milky Way that have no particular identity.

Due to the characteristics of its explosion, the team initially thought that ASKAP J173608.2-321635 could be a pulsar, a rotating dead star whose brightness changes regularly for observers on Earth. But the fluctuations in the brightness of this object were not regular, and its lack of other electromagnetic waves means that it does not look like a small brown dwarf or a star. magnetic Very magnetic. Kaplan said it may have been an “alien” pulsar, but the team won’t know for sure their current data.

Even if ASKAP J173608.2-321635 is not seen again, they expect future observations to determine whether the object is the rule or the exception, ie if the source is the first of a class of objects not yet observed or something like that. Different.

Instead of jumping from one radio telescope to another in the future, the team hopes to use square kilometer array (SK), the world’s largest radio telescope with 130,000 antennas, for your future observations of distant radio sources. The matrix is ​​expected to begin routine scientific observations at the end of this decade.