Astronomers have produced the most comprehensive radio emission image of the actively feeding supermassive black hole closest to Earth. The emission is driven by a central black hole in the Centaurus A galaxy, some 12 million light-years away. As the black hole feeds on the falling gas, it ejects material almost at the speed of light, causing ‘radio bubbles’ to grow over hundreds of millions of years.
When viewed from Earth, Centaur A’s eruption now stretches eight degrees across the sky, the length of 16 full moons positioned side by side. It was captured with the Murchison Widefield Array (MWA) telescope in the Western Australian outback. The research was published in the journal Nature Astronomy. Lead author Dr Benjamin McKinley of the Curtin University node of the International Center for Radio Astronomy Research said the image reveals spectacular new details of the galaxy’s radio emission.
“These radio waves come from material that is absorbed by the supermassive black hole in the middle of the galaxy,” he said in a statement. ‘It forms a disk around the black hole, and as matter tears closer to the black hole, powerful jets form on either side of the disk, expelling most of the material into space, at distances of probably more than a million Light years. “Previous radio observations could not handle the extreme brightness of the jets and the details of the larger area surrounding the galaxy were distorted, but our new image overcomes these limitations.”
“Previous radio observations could not handle the extreme brightness of the jets and the details of the larger area surrounding the galaxy were distorted, but our new image overcomes these limitations.” Centaurus A is the closest radio galaxy to our own Milky Way. “We can learn a lot from Centaurus A in particular, simply because it is so close and we can see it in such detail,” said Dr. McKinley.
Astrophysicist Dr. Massimo Gaspari, from Italy’s National Institute of Astrophysics, said the study corroborated a novel theory known as ‘Chaotic Cold Accretion’ (CCA), which is emerging in different fields.
‘In this model, the cold gas clouds condense in the galactic halo and rain down on the central regions, feeding the supermassive black hole. Triggered by this shower, the black hole reacts vigorously by launching energy through radio jets that inflate the spectacular lobes that we see in the MWA image. This study is one of the first to probe the multiphase CCA ‘climate’ in such detail over the full range of scales, “he explained.