Astronomers reveal best image yet of mysterious ORCs in space
Data from SARAO's MeerKAT radio telescope data (green) showing the odd radio circles, is overlaid on optical and near infra-red data from the Dark Energy Survey. Credit: J. English (U. Manitoba) / EMU / MeerKAT / DES(CTIO)

An international team of astronomy using the world's most capable radio telescopes has pulled into focus astronomy's newest mystery objects.

odd radio circles quickly became objects of fascination when first revealed in 2020 by the ASKAP radio telescope, owned and operated by Australia's national science agency. There were many theories on what causes them.

A new detailed image, captured by the South African Radio Astronomy Observatory's MeerKAT radio telescope and published today in Monthly Notices of the Royal Astronomical Society, is providing researchers with more information to help narrow down those theories.

There are three leading theories about what causes ORCs.

  • They could be the remnant 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 spewing out of the galaxy's center
  • They might be the result of a starburst "termination shock" from the production of stars in the galaxy.

ORCs have only been detected using radio telescopes, with no signs of them when researchers have looked for them using other telescopes.

The Inter-University Institute for Data Intensive Astronomy compiled the image from the data and said that it will provide more clues.

People often want to show that their observations are in line with their best knowledge. It is more exciting to discover something new that defies our current understanding.

The rings are about a million light years across, which is 16 times bigger than our own. The odd radio circles are hard to see.

One of the authors on the paper said that only five radio circles have ever been seen in space.

We know ORCs are rings of faint radio emissions surrounding a galaxy with a highly active black hole at its center, but we don't yet know what causes them, or why they are so rare.

The Chief Scientist of the Australia Telescope National Facility said that ASKAP and MeerKAT are working together to find and describe these objects quickly and efficiently.

The teams of people involved and the technology available make astronomy projects better.

ASKAP and MeerKAT are both related to the international SKA project. Our understanding of odd radio circles is enabled by these telescopes working together.

More than a dozen countries, including the UK, Australia, South Africa, France, Canada, China and India, support the SKA Observatory, which is one of the most sensitive radio telescopes in the world.

The SKA telescopes will find many more ORCs and be able to tell us more about the lifecycle of the universe.

Until the SKA becomes operational, ASKAP and MeerKAT are set to change our understanding of the universe faster than ever before.

Over the course of 15 years, hundreds of people in South African research organizations, industry, universities, and government worked together to build MeerKAT. It's a testament to their skill and dedication and of those SARAO colleagues who maintain, operate, and continue to develop MeerKAT that it's now a much sought-after telescope.

Research into odd radio circles makes for fantastic collaboration, remarked Dr. Bärbel Koribalski, who discovered an odd radio circle in 2021. You need a lot of people with different experience. My team includes everyone from students to senior researchers, who work in data processing to theoretical modeling. There are many exciting discussions to be had.

More information: Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac701 Journal information: Monthly Notices of the Royal Astronomical Society Citation: Astronomers reveal best image yet of mysterious odd radio circles in space (2022, March 21) retrieved 21 March 2022 from This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.