Radio waves

Space: mysterious radio waves arrive 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 what is emitting them. They seemingly turn on and off at random, and their source must be unlike anything we’ve seen before.

The source of this radiation has been dubbed “Andy’s object” after Ziteng Wang of the University of Sydney in Australia, who is called Andy and was the first to discover radio waves. He and his colleagues spotted the shows 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 occasionally flared up for a few weeks, but was dark most of the time. When he finally re-ignited in February of this year, several months after the initial detection, they pointed some of the most powerful non-radio telescopes we have at him and saw nothing. “We’ve looked at all of the other possible wavelengths, from infrared to optics to x-rays, and we don’t see anything, so it doesn’t seem consistent with any type of star we understand.” says David Kaplan of the University of Wisconsin-Milwaukee, who was part of the research team.

The fact that it was not visible at 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, the polarization of the radio waves coming from it indicates that he probably has a strong magnetic field. During the flares, its brightness varied 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 weird traits. “It’s an interesting object that has foiled any attempt at an explanation,” Kaplan says. “It might turn out to be part of a known object class, just a weird example, but it will push the boundaries of how we think these classes behave. “

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

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