In the early 1960s, successfully identifying the optical analogue of the sourcepowerful discovery that time and was baptized in 3C 273, note that it looks like a star, but it is the light is strongly redshifted. As part of the relativism of that time is already quite well developed, which would mean that it is on the billions distance and that therefore it radiates to be visible from afar, quantities amazing and almost unbelievable, because no ordinary star or even stellar explosion can physically explain it.
Several hypothesesproposed to explain the existence of this source and others like it that radio astronomers will discover within the same decade. The conservative hypothesis suggested that they were indeed stars, but very massive and therefore with a significant redshift due to their field of view. famous prediction since its opening . Then these stars would be close and their then the inner would have nothing extraordinary.
Other researchers in the same decade whenquickly established after opening in 1965, more daring and exploratory, like Igor Novikov and proposed the idea that what we already call may be parts expansion of which during was postponed (speculation lagging nucleus). They will even go so far as to suggest that these cosmic phenomena are the other end of wormholes ejecting which they took in the form in another part of space or even in another universe.
We think we now know thatcontaining accreting agent, .
From quasars to ORCs
Since 2019, however, British-Australian astronomer Ray Norris and his colleagues have been very puzzled by the handful of objects they have detected usingAustralian Pathfinder Array of Square Kilometers (Askap), an Australian network of radio telescopes that served as the prototype for the long-awaited(SKA), a virtual giant radio telescope project with a collecting surface equivalent to one square kilometer, is underway and integrates several instruments.
Askap’s first unusual object was named ORC 1, ORC for ” weird radio circles “, which can be translated as ” weird radio circles “.
As their name implies, they appeared on the radio as rings, but nothing in the visible region was associated with them, which ruled out the hypothesis that they could be remnants.or more Who else can look like this. Also, it is unlikely that these are radio lobes associated with supermassive black hole jets because they are much more irregular.
The distance, and therefore the size of these circles, had not yet been determined at the outset. But that just changed and posting in Royal Astronomical Society Monthly Notices (MNRAS), which can be viewed free of charge at, starts to give some answers.
Astronomers mobilizedalso the predecessor of SKA, to whom we are already indebted to better observe ORC 1. It then became possible to find a new radio source at the center of the radio circle, a source that could be associated with the galaxy. After all, the data now collected suggests that we are in the presence of a ring located a billion light-years from Earth. and, accordingly, about a million light years in diameter.
Similar conclusions were made using MeerKAT, and now it seems that the ORCs are giant bubbles of very hot gas, the outlines of which seem brighter because we see in the cut a large thickness of matter containing relativistic electrons forming a plasma immersed fromand which radiates respectively. The presence of magnetic fields is detected by the polarization of radio waves measured using MeerKAT. This type of radiation is called synchrotron because it is observed in these particle accelerators on Earth, is well known in the Milky Way, and also in space. .
Bubbles appear at the center of the discovered galaxies, and therefore it seems clear and established that they were blown out by these galaxies, as if it were the shock wave front of a quasi-spherical explosion.
Artist’s impression of the formation of one of the strange radio circles from an explosion in the central galaxy. It is believed that the bubble from the explosion took 1 billion years to grow to the size we know today. Radio circles are so large (millions of light years in diameter) that they extend beyond their original galaxies. © Sam Moorfield/CSIRO
However, the nature of the explosion remains unclear. It may be an unpredictable and unobservable phenomenon when two supermassive black holes collide afterfrom two galaxies.
It can also be a sudden formationthe gravitational force of about a million stars in the galaxy, with the birth of these stars causing a sudden outburst of plasma leaving the galaxy.
We should know more with an additional resolution increase once SKA is fully operational.