Centaurus A is a giant elliptical active galaxy 12 million light-years away. At its heart lies a black hole with a mass of 55 million suns. This image shows the galaxy at radio wavelengths, revealing vast lobes of plasma that reach far beyond the visible galaxy, which occupies only a small patch at the centre of the image. The dots in the background are not stars, but radio galaxies much like Centaurus A, at far greater distances. Credit: Ben McKinley, ICRAR/Curtin and Connor Matherne, Louisiana State University
Astronomers have produced the most comprehensive image of radio emission from the nearest actively feeding supermassive
Centaurus A is a giant elliptical active galaxy 12 million light-years away. At its heart lies a black hole with a mass of 55 million suns. This composite image shows the galaxy and the surrounding intergalactic space at several different wavelengths. The radio plasma is displayed in blue and appears to be interacting with hot X-ray emitting gas (orange) and cold neutral hydrogen (purple). Clouds emitting Halpha (red) are also shown above the main optical part of the galaxy which lies in between the two brightest radio blobs. The ‘background’ is at optical wavelengths, showing stars in our own Milky Way that are actually in the foreground. Credit: Connor Matherne, Louisiana State University (Optical/Halpha), Kraft et al. (X-ray), Struve et al. (HI), Ben McKinley, ICRAR/Curtin. (Radio)
The research was published on December 22, 2021, in the journal Nature Astronomy.
Lead author Dr. Benjamin McKinley, from the Curtin University node of the International Centre for Radio Astronomy Research (
A video showing the radio galaxy, Centaurus A, which hosts the closest actively feeding black hole to Earth. The video shows the apparent size of the galaxy at optical, X-ray, and submillimeter wavelengths from Earth when compared to the Moon. It then zooms out to show the enormous extent of the surrounding bubbles that are observed at radio wavelengths. Astronomers have produced the most comprehensive image of radio emission from the nearest actively feeding supermassive black hole to Earth.
Centaurus A is the closest radio galaxy to our own
Tile 107, or “the Outlier” as it is known, is one of 256 tiles of the MWA, located 1.5km from the core of the telescope. Lighting the tile and the ancient landscape is the Moon. Credit: Pete Wheeler, ICRAR
Astrophysicist Dr. Massimo Gaspari, from Italy’s National Institute for Astrophysics, said the study corroborated a novel theory known as ‘Chaotic Cold Accretion’ (CCA), which is emerging in different fields.
“In this model, clouds of cold gas condense in the galactic halo and rain down onto the central regions, feeding the supermassive black hole,” he said.
“Triggered by this rain, the black hole vigorously reacts by launching energy back via radio jets that inflate the spectacular lobes we see in the MWA image. This study is one of the first to probe in such detail the multiphase CCA ‘weather’ over the full range of scales,” Dr. Gaspari concluded.
Dr. McKinley said the galaxy appears brighter in the center where it is more active and there is a lot of energy.
“Then it’s fainter as you go out because the energy’s been lost and things have settled down,” he said.
“But there are interesting features where charged particles have re-accelerated and are interacting with strong magnetic fields.”
MWA director Professor Steven Tingay said the research was possible because of the telescope’s extremely wide field-of-view, superb radio-quiet location, and excellent sensitivity.
“The MWA is a precursor for the Square Kilometre Array (SKA)—a global initiative to build the world’s largest radio telescopes in Western Australia and South Africa,” he said.
“The wide field of view and, as a consequence, the extraordinary amount of data we can collect, means that the discovery potential of every MWA observation is very high. This provides a fantastic step toward the even bigger SKA.”
Reference: “Multi-scale feedback and feeding in the closest radio galaxy Centaurus A” by B. McKinley, S. J. Tingay, M. Gaspari, R. P. Kraft, C. Matherne, A. R. Offringa, M. McDonald, M. S. Calzadilla, S. Veilleux, S. S. Shabala, S. D. J. Gwyn, J. Bland-Hawthorn, D. Crnojević, B. M. Gaensler and M. Johnston-Hollitt, 22 December 2021, Nature Astronomy. DOI: 10.1038/s41550-021-01553-3
The Murchison Widefield Array is the MWA is managed and operated by Curtin University on behalf of an international consortium, and is located on the Murchison Radio-astronomy Observatory in Western Australia. The observatory is managed by CSIRO, Australia’s national science agency, and was established with the support of the Australian and Western Australian Governments. We acknowledge the Wajarri Yamatji as the traditional owners of the observatory site.
The Pawsey Supercomputing Research Centre in Perth–a Tier 1 publicly funded national supercomputing facility–helped store and process the MWA observations used in this research.
