Cape Town - Astronomers have been working tirelessly to study astronomy’s latest phenomenon called odd radio circles (ORC).
First revealed by the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, owned and operated by Australia’s national science agency the Commonwealth Scientific and Industrial Research Organisation (CSIRO), odd radio circles quickly became objects of fascination.
Theories on what caused them ranged from galactic shockwaves to the throats of wormholes.
A detailed image captured by the South African Radio Observatory’s MeerKAT telescope has been able to provide researchers with more information on the possible cause of the ORCs.
Leading theories include remnants of a huge explosion at the centre of the galaxy caused by a merge of two black holes, powerful jets of particles spewing out of the galaxy or a result of ‘terminal shock’ from the production of stars.
Professor Ray Norris, from Western Sydney University and one of the authors on the paper, said: “We know ORCs are rings of faint radio emissions surrounding a galaxy with a highly active black hole at its centre, but we don’t yet know what causes them, or why they are so rare.”
To date ORCs have only been detected using radio telescopes, with no signs of them when researchers have looked for them using optical, infrared, or X-ray telescopes.
Dr Jordan Collier, a member of the UCT Astronomy Department, is part of the international research team and commented on the latest observation.
“To understand its physical nature more clearly, we wanted to look at how its brightness changed across frequency and its polarisation structure,” he said.
He said the brilliant thing about collaborative work is that, within the international team of experts, there are different people working within their different fields of expertise, to maximise the amount of research done.
“To me, it’s much more exciting to discover something new that defies our current understanding. Continuing to observe these odd radio circles will provide researchers with more clues.”
As research continues, the team are working to get to the root cause of the ORCs to be able to go in-depth into their findings and to inform the public about what makes them so fascinating.
Dr Fernando Camilo, chief scientist of the South African Radio Astronomy Observatory, which built and operates MeerKAT, explained: "The ORC project is a great example of the clever use of MeerKAT by its users, playing to its strengths: ASKAP observes large swaths of the sky and can discover relatively rare types of objects; MeerKAT can then follow up to study them in greater detail.”
To really understand odd radio circles scientists will need access to even more sensitive radio telescopes such as those of the SKA Observatory, which is supported by more than a dozen countries including South Africa, Australia, the UK, France, Canada, China and India.