In September 2019, my colleague Anna Kapinska made a presentation showing interesting things while browsing our new radio astronomical data. She began to see very strange shapes that could not easily fit into any known type of to-budget.
Of those, labeled by Anna WTF?, Was a picture of a haunted circle of radio emissions, hanging in space like a cosmic smoke-ring.
None of us have ever seen anything like it before, and we have no idea what it is. A few days later, our colleague Emil Lank found another one that was even more ugly than Anna.
Anna and Emile were examining new images of pilot observations for CSIRO’s revolutionary new Australian Square Kilometer Array Pathfinder (ASKAP) telescope for the Evolutionary Map of the Universe (EMU) project.
EMU plans to boldly investigate parts of the universe where no telescope has gone before. It can do this because ASKAP can survey large parts of the sky very quickly, detects previously reached depths in small areas of the sky, and is particularly sensitive to sculpting, dispersing objects like this.
I predicted a few years ago that this discovery of the unknown could lead to an unexpected discovery, which I call the WTF. But none of us expected to find something, very quickly, as expected.
Due to the enormous data volumes, I expect that search will be done with the help of machine learning. But these discoveries were made with the good old-fashioned eyeball.
Hunting O.R.C.
Our team found the rest of the data by eye, and we found some more of the mysterious round blobs. We dubbed them ORC, which stands for “Strange Radio Circles”.
But the big question, of course, is: “What are they?”
Initially we suspected an imaging artifact, probably caused by a software error. But we soon confirmed that they are real, using other radio telescopes. We have no idea yet how big or far they are.
They could be objects in our galaxy, maybe a few light years ahead, or they could be in the universe and millions of light years away.
When we look at images taken with an optical telescope at the ORC position, we see nothing. Radio emission rings may be caused by clouds of electrons, but why do we not see anything in the visible wavelength of light?
We don’t know, but finding a puzzle like this is the dream of every astronomer.
We know what they are not
We have ruled out many possibilities of what an ORC could be.
Could it be supernova remnants, left behind by clouds of debris when the star of our galaxy explodes? No. They are far from most of the stars in the galaxy and there are many of them.
Could they be rings of radio emission that are sometimes found in galaxies passing through sharp explosions of stellar formation. Again, no. We do not see any underlying galaxy that hosts star formation.
Could they be the huge lobes of radio emissions that we see in radio galaxies caused by a jet of electrons escaping from the atmosphere of a supermassive black hole? Not possible, because ORCs are very clearly spherical, unlike clustered clouds, as we see in radio galaxies.
Could it be Einstein’s rings, in which radio waves from a distant galaxy are rotated by the gravitational field of a galaxy’s cluster? Not yet. ORCs are very symmetrical, and we do not see clusters in their center.
A real secret
In our paper about ORC, which is next The Publications of the Astronomical Society of Australia, We go through all the possibilities and conclude that these mysterious blobs do not look like anything we already know.
So we need to explore things that may have existed but have not yet been observed, such as massive shockwaves from some explosions in distant galaxies. Such explosions may have something to do with the collision of a neutron star and a black hole producing fast radio explosions or gravitational waves.
Or maybe they are something completely different. Two Russian scientists have also suggested that the ORC may have a “throat” of deworming in space time.
From the fist we have found so far, we estimate that there are about 1000 ORCs in the sky. My colleague Barbel Koribalski notes that the search is now on with telescopes around the world to find more ORCs and understand their cause.
It is a difficult task, as the ORC is very dizzy and difficult to find. Our team puts all of these ideas and more and more into consideration, while Eureka is hoping for the moment when one of us, or someone else, suddenly has a flash of inspiration that solves the puzzle.
It is an exciting time for us. The purpose of most astronomical research is to improve our knowledge of the universe or to test theories. Very rarely do we find ourselves stumbling upon a new type of object object that no one has seen before, and trying to figure out what it is.
Is it a completely new phenomenon, or something we already know but have seen strangely? And if it is really completely new, how can it change our understanding of the universe? Check out this space!
Ray Norris, Professor, School of Science, Western Sydney University.
This article is republished from the talk under the Creative Commons license. Read the original article.
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