Volcanic ‘activity’ in black holes blows monumental bubbles of hundreds of thousands of light-years
An international team of researchers observed the full extent of the evolution of hot gas produced by an active black hole for the first time. As it evolves, the hot gas encompasses a much larger area than previously thought and even impacts objects residing at great distances. Their study is published in Nature Astronomy.
The team included astronomers from the Leiden Observatory and the Netherlands Institutes for Radio Astronomy (ASTRON) and Space Research (SRON). Their findings came from studies of Nest200047 – an otherwise innocuous group of galaxies about 200 million light years away that houses a spectacular black hole in the galaxy at its centre.
Bubbles and filaments of hot gas
The black hole is actively accreting any surrounding matter and releasing powerful streams of particles as a result. These particles have formed pairs of bubbles and filaments of hot gas that have gradually drifted away from the black hole, reaching distances of hundreds of thousands of light-years and impacting anything that stands in their way. These structures that are now observable are strongly reminiscent of the smoke streams produced in the Earth’s atmosphere by volcanic eruptions.
‘Our investigation shows how the gas bubbles accelerated by the black hole are expanding and transforming in time. Indeed, they create spectacular mushroom-shaped structures, rings and filaments that are similar to those originating from a powerful volcanic eruption on planet Earth,’ states Marisa Brienza of the University of Bologna, who led the study.
An astonishingly large answer
Co-author Timothy Shimwell (ASTRON and Leiden University) is thrilled with the result. ‘For many years, researchers have been trying to figure out how much of the surrounding area a black hole can influence. The images we have created of this incredible system show that the answer is astonishingly large. The black hole doesn’t just influence the host galaxy but instead it impacts a vast intergalactic environment which may contain hundreds of other galaxies, and it will affect aspects such as the rate at which stars form in those galaxies.'
Travelling in time
Observations that made this research possible were conducted by the Low Frequency Array (LOFAR) and the extended Roentgen Survey with an Imaging Telescope Array (eROSITA). LOFAR, which is centred in the Netherlands, is the largest low-frequency radio telescope in the world, and eROSITA, is a state-of-the-art space telescope. These facilities have allowed researchers to ‘travel in time’ and witness an eruption from a black hole more than 100 million years ago and map out its consequences. Much like studying artefacts from ancient volcanic eruptions on Earth, such as those in Pompei.
LOFAR is proving to be amongst the world’s most prolific radio telescopes. ‘This is yet another fantastic scientific breakthrough that LOFAR has facilitated and it’s opened up a new avenue of research that is going to be actively pursued” says Huub Rottgering, Scientific Director of the Leiden Observatory. This comes after substantial and sustained development efforts, with Leiden astronomer Reinout van Weeren noting that ‘the techniques required to fully exploit a pioneering telescope such as LOFAR take years to develop, and rely on some of the nation’s largest compute facilities to operate. So getting this type of result is a mammoth effort, but one that is very gratifying to be part of.’
‘A snapshot of the oldest AGN feedback phases’ is published in Nature Astronomy. It is the result of a combined effort of experts in radio, optical and X-ray astronomy from the University of Bologna, INAF, ASTRON, Leiden Observatory, Hamburger Sternwarte, Kazan University, Space Research Institute (IKI), Max Planck Institute for Astrophysics, University of Hertfordshire, SRON, Observatoire de Paris.
Header image: Here we see Nest200047, a structure that has revealed the archeological riches associated with a hundred million years of black hole activity. The black hole resides in a galaxy at the centre of the image and is surrounded by bright jets of plasma that are emitted from its poles as it accretes the surrounding matter. Over time these jets form bubbles and filaments that gradually drift away from their the origin and impact everything in their path. This reveals the extensive impact that a black hole has, not just on the galaxy that hosts it, but on a gigantic area that may contain hundreds of other galaxies and a lot of other material.