The mystery of strange objects in space that envelops entire galaxies has been revealed

Summary

Astrophysicist Ray Norris and colleagues have discovered that the mysterious "Odd Radio Circles" (ORCs) enveloping galaxies are likely the result of massive explosions or starburst events originating from the central galaxies, as revealed by observations from the MeerKAT radio telescope.

Abstract

In 2019, Ray Norris and his team identified enigmatic glowing rings in space, dubbed "Odd Radio Circles" (ORCs), using the CSIRO radio telescope. Recently, more detailed analysis with the South African MeerKAT telescope has shown that these circular objects, each about a million light-years in diameter, surround faint galaxies. The high-resolution images from MeerKAT indicate that the ORCs are likely produced by enormous explosions of hot gas or intense star formation episodes within the central galaxies. These galaxies are estimated to be about a billion light-years away, emphasizing the vast scale of these formations. The MeerKAT observations also mapped the polarization of radio waves, suggesting that the energy released from the central galaxies is interacting with the surrounding intergalactic medium. While the exact cause remains uncertain, potential explanations include the merging of supermassive black holes or a rapid burst of star formation resulting in a shock wave. Only five ORCs have been detected so far, and they remain invisible in optical, infrared, or X-ray wavelengths, which contributes to their rarity and ongoing mystery. A forthcoming study detailing these findings is set to be published in the "Monthly Notices of the Royal Astronomical Society."

Opinions

Ray Norris and his team are confident that the central galaxies within the ORCs are the source of these enormous formations, based on the MeerKAT radio telescope data.
The scientists hypothesize that the ORCs could be the result of cataclysmic events such as the collision of two supermassive black holes or the rapid formation of millions of stars in a brief period.
The rarity of ORCs is attributed to the infrequency of such dramatic cosmic events.
The MeerKAT observations have been instrumental in providing detailed images and polarization data that have advanced the understanding of ORCs.
Despite the progress, the mystery of ORCs is not fully resolved, as they have only been observed with radio telescopes and remain undetected in other parts of the electromagnetic spectrum.

The mystery of strange objects in space that envelops entire galaxies has been revealed

In 2019, astrophysicist Ray Norris from the University of Western Sydney and his colleagues discovered strange glowing rings in space with the help of the CSIRO radio telescope. These structures did not resemble anything they had seen before and only now have they come one step closer to revealing their secrets.

Scientists have called these circular objects “unusual radio circles” (ORCs). Recently, they analyzed them in more detail through the South African MeerKAT telescope and saw that each of them is located around a galaxy that they could not notice before because of its low brightness. They concluded that the circles were most likely huge explosions of hot gas, about a million light-years in diameter, emanating from the central galaxy.

A million light-years in diameter

“Now, with the help of the MeerKAT radio telescope, we have received beautiful images of one of the rings. They showed incredible details. MeerKAT spotted a small spot of radio broadcast in the center of the ring, which coincided with the position of the galaxy. So, now we are pretty sure that ORC originates from that galaxy “, states Norris.

“We have seen these central galaxies in other ORCs as well. “We believe that these rings surround galaxies that are about a billion light-years away, which means that these circular formations are huge — they are about a million light-years in diameter,” he added.

The collision of black holes or the birth of millions of stars

MeerKAT also mapped the polarization of radio waves, and data show that the explosion in the central galaxy collided with gas outside the galaxy. But the question remains what caused such a big explosion. Scientists believe that there are two possible causes. One is the collision of two supermassive black holes. Such an event would release a huge amount of energy, enough to create an ORC. Another possibility is that the central galaxy has gone through a phase of intense star birth, in which millions of them suddenly formed from gas. Such a stellar “burst” could trigger a hot gas burst or a strong shock wave. Both of these events are rare in space, which explains why ORCs are so rare — only five have been spotted so far. Their mystery, however, has not yet been completely solved. For now, scientists have registered them only with radio telescopes, they are not visible on optical, infrared, or X-ray wavelengths, “Index” reported. A study called “MeerKAT uncovers the physics of the Odd Radio Circle” will soon be published in the “Monthly Notices of the Royal Astronomical Society”.