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Feast your eyes on the best view in radio waves of Centaurus A, a nearby galaxy whose supermassive black hole has been erupting for millions of years. This activity has created jets that stretch for a million light-years – and if they were visible to our eyes, they would wider than 16 full moons in the sky.
The incredible picture was possible thanks to Murchison Widefield Array (MWA) telescope in outback Western Australia and the observations are reported in the journal Nature Astronomy. Centaurus A is the closest radio galaxy to our own Milky Way, just 12 million light-years away. Studying it in detail opens a window to an important class of galaxies.
“These radio waves come from material being sucked into the supermassive black hole in the middle of the galaxy,” Dr Benjamin McKinley, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said in a statement.
“It forms a disc around the black hole, and as the matter gets ripped apart going close to the black hole, powerful jets form on either side of the disc, ejecting most of the material back out into space, to distances of probably more than a million light-years.
“Previous radio observations could not handle the extreme brightness of the jets and details of the larger area surrounding the galaxy were distorted, but our new image overcomes these limitations.”
The study is so detailed that it allowed the testing of a new theory called Chaotic Cold Accretion (CCA). This idea tries to explain the motion of gas surrounding the galaxy, how it falls back into the galaxy, and how it might end up feeding the supermassive black hole.
“In this model, clouds of cold gas condense in the galactic halo and rain down onto the central regions, feeding the supermassive black hole,” astrophysicist Dr Massimo Gaspari, from Italy’s National Institute for Astrophysics, explained.
“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.”
The work also combines radio images with X-rays and visible observations, providing an incredible look at the galaxy and important insights into the physics of the supermassive black holes. The one actively spewing inside this galaxy weighs a whopping 55 million times the mass of our Sun.
