Located in the Northern Cape of South Africa, MeerKAT , this telescope that listens to radio signals from deep space , has made it possible for us to see the sharpest image of odd radius circles (ORC), large circular astronomical objects that shine around Earth. the edges in radio wavelengths.
What creates this cosmic mystery?
Its rings are gigantic, about a million light years in diameter, that is, it is 16 times wider than our galaxy, the Milky Way; and it looks like a smoking ring. What is it? The truth is that astronomers are still not sure. The universe is full of peculiar objects.
Like many astronomical anomalies, the name tells you all: they are round spots of radio emissions that cannot be explained by known objects or phenomena. In addition, they represent a fairly recent phenomenon, since the first one was discovered in September 2019 and only five ORCs have been confirmed so far.
These ORCs are part of the “WTF?” ( what the fuck , ¿qué carajo?) in which all those inexplicable phenomena or objects for current astronomy are shown. In 2019, astronomer Anna Kapinska included a new and unusual object in her inventory of cosmic oddities: a faint, ghostly circle about 1 billion light-years from Earth. Shortly after, astronomer Emil Lenc found a second circle. They were then baptized as “odd radio circles” or ORC.
How do we see them? What wavelength are they on?
It is curious because, as huge as these objects are, they are difficult to see: they are only visible to radio telescopes. They are not seen with either X-ray telescopes, like NASA’s Chandra, or infrared telescopes like James Webb.
According to the latest observations of ORC1C, they show that the layers of this object are created by the radiation of accelerated electrons and have a complex internal structure made of multiple arcs.
“Scientists often want to explain their observations and show that it aligns with our best knowledge. For me, it is much more exciting to discover something new, which challenges our current understanding , ”said Jordan Collier, from the Interuniversity Institute for Data Intensive Astronomy and co-author of the work published in the journal Monthly Notices of the Royal Astronomical Society.
cosmic detectives
The three main theories that explain what causes these ORCs are these:
- They could be the remnants of a huge explosion at the center of their host galaxy, like the merger of two supermassive black holes.
- They could be powerful jets of energetic particles coming out of the center of the galaxy
- They could be the result of a starburst “termination shock” of star production in the galaxy.
“We know that ORCs are rings of faint radio emissions surrounding a galaxy with a very active black hole at its center, but we don’t yet know what causes them or why they are so rare,” said Ray Norris of Western Sydney University. and CSIRO and also co-author of the work.
“For now, ASKAP and MeerKAT are working together to find and describe these objects quickly and efficiently,” said Elaine Sadler, chief scientist at CSIRO’s Australian National Telescope Facility and co-author of the study.
For now, the mysterious radius circles will remain a rarity. Collecting more data will be key, and for this, everything will become more interesting when the Square Kilometer Array (SKA) radio telescope of an area of 1 square kilometer, is active by 2027.
Referencia: “MeerKAT uncovers the physics of an Odd Radio Circle” by Ray P. Norris, J. D. Collier, Roland M. Crocker, Ian Heywood, Peter Macgregor, L. Rudnick, Stas Shabala, Heinz Andernach, Elisabete da Cunha, Jayanne English, Miroslav Filipovic, Baaerbel S. Koribalski, Kieran Luken, Aaron Robotham, Srikrishna Sekhar, Jessica E. Thorne and Tessa Vernstrom, 21 March 2022, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stac701
