Astronomers question their science after distant galaxy emits strange radio signals that are ‘facing the wrong way’

Representative image of the Galaxy MACS J0717 cluster

(X-ray: NASA/CXC/SAO/van Weeren et al.; Optical: NASA/STScI; Radio: NSF/NRAO/VLA)

The apple falls from the tree because gravity follows precise rules on our planet. We feel sleepy after eating rice because it helps release calming hormones in our body. In nature, everything is organized and in place. But every now and then, he likes to throw a wrench in the works, apparently just to play with bewildered scientists brave enough to study natural law.

That’s exactly what’s happening with a particularly cheeky galaxy cluster called Abell 3266, whose recent strange antics have astronomers and physicists pulling their hair out and scurrying through their books for an explanation. for his strange behavior.

But before we get into the complicated (and wonderful) cosmic mess that is these galaxy clusters, let’s try to understand it in terms that everyone is extremely familiar with: the fossils!

Fossils of ancient cosmic cities

We know that dinosaurs and other flora existed long before us because they left tangible evidence behind that we could study. In the same way that we could date these ancient fossils to determine exactly how old they were, scientists also use similar techniques to study the radio emissions of dying supermassive black holes in space, which are in essentially “fossils” of these magnificent cosmic giants.

Radio emissions are a type of “invisible” light given off by celestial bodies that radio astronomers study to understand their composition and age, among other things. His research reveals some of the universe’s most amazing and best-kept secrets, such as the origin of the Big Bang through the study of the infamous cosmic microwave background radiation.

Most of what makes a cluster is plasma – a chaotic state of matter that forms when gas is heated in pipes to 10 million degrees Celsius. When radio waves are generated through this plasma, certain familiar patterns emerge, which scientists categorize to gain insight into the galactic environment.

So what’s going on with the Abell 3266?

While the particle size of many of these radio relics from the collisions of clusters and supermassive black holes still remains elusive to us, their mere existence provides fundamental answers to some obvious questions. If there is a shadow, we know there is something dark to cast it. But Abell, the group from 800 million light years away, was already an enigma, because despite meeting all the conditions, it cast no proverbial shadow!

The group had no discernible radio relics until recently. And when Australian scientists tried to study it using the combined power of more than three separate powerful satellite arrays, they noticed that some of the extremely elusive emissions defied everything they thought they knew about them.

Radio emissions emanating from one part of the cluster formed a sonic boom-like arc, likely powered by shock waves traveling through the plasma from a massive cosmic collision. However, its highly unusual concave shape puzzled radio scientists, as they had never seen anything like it before. Plus, its odd orientation facing the center of the group earned it the nickname “the relic of the wrong way.”

“If it’s a shock wave, you might think it would bend like a bow around the edge, but this one is flipped,” explained one of the astrophysicists behind the study, Dr Tessa Vernstrom. “So we don’t really understand what he’s telling us.”

A new kind of science?

Dr Vernstrom adds that her team thinks this is real and likely not an error from image processing. Furthermore, the unexpected brilliance of the relic also meant that there were massive gaps in the understanding of how these radio fossils behave, and that scientists had to go back to the drawing board to come up with explanations.

“Maybe there’s some kind of new physics going on there that we haven’t fully understood when our models can’t match the observations,” she added.

Colliding galaxy clusters, such as some in Abell 3266, are eerie places in space that leave scientists reeling with excitement, but also rattle their bones. These environments have so much plasma and dark matter activity that they produce a whole variety of data that would otherwise be impossible to collect in a laboratory.

Abell 3266, in particular, is a special cluster because it has many anomalies and rare phenomena that are absent from most other observed clusters, or simply have not yet been discovered. However, it also serves as a testament to the growing power of radio telescopes and the exciting opportunity to study the rest of the universe.

“Looking at radio, you see a different kind of physics than when you look at other wavelengths,” explains Dr Vernstrom. “We’re going to see a lot more of this kind of thing.”

The research was published in Monthly Notices of the Royal Astronomical Societyand can be accessed here.


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