Radio waves

Space: Mysterious radio waves are coming from the center of the galaxy

Illustration of radio waves coming from the galactic center

Sebastien Zentilomo

Strange radio signals are coming from the center of the galaxy and we don’t know exactly what is emitting them. They turn on and off seemingly randomly, and their source must be unlike anything we’ve seen before.

The source of this radiation was dubbed “Andy’s Object” after Ziteng Wang at the University of Sydney in Australia, whose name is Andy and who discovered radio waves. He and his colleagues spotted the emissions six times in 2020 using Australia’s Square Kilometer Array Pathfinder radio telescope. They made further observations with the MeerKAT radio telescope in South Africa.

The researchers found that the object flared up occasionally for a few weeks, but was dark most of the time. When it finally came back on in February of this year, several months after the initial detection, they pointed at some of the most powerful non-radio telescopes we’ve seen and saw nothing. “We’ve looked at all the other wavelengths we could, from infrared to optical to x-rays, and we can’t see anything, so it doesn’t seem to match any type of star we’re looking at. understand,” says David Kaplan at the University of Wisconsin-Milwaukee, who was part of the research team.

The fact that it was not visible in any other wavelength ruled out several possible explanations for this object, including normal stars and magnetars, which are neutron stars with strong magnetic fields.

Whatever Andy’s object is, the polarization of the radio waves coming from it indicates that it likely has a strong magnetic field. During flares, its brightness varied by up to a factor of 100, and these flares faded extraordinarily quickly – as fast as a single day – facts that suggest the object is small.

But no astronomical body we know of matches all of these odd traits. “It’s an interesting object that has baffled any attempt to explain it,” Kaplan says. “It might turn out to be part of a known class of objects, just an odd example, but that will push the boundaries of how we think these classes behave.”

Journal reference: The Astrophysical Journal, DOI: 10.3847/1538-4357/ac2360

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