Black holes are like volcanoes: they produce bubbles, rings and filaments of 'intergalactic smoke' that trace activity back in time to 200 million years ago, revealing their great impact on the evolution of the intergalactic medium.
Observing these spectacular hot gas structures in detail for the first time was an international research group involving experts from the University of Bologna and the National Institute of Astrophysics (Inaf).
The results are published in Nature Astronomy.
The study focused on a group of about twenty galaxies, called the Nest200047 system, about 200 million light years away. The central galaxy of the system hosts an active black hole around which several pairs of gas bubbles of different ages and mysterious filaments of magnetic fields and relativistic particles with dimensions up to hundreds of thousands of light years have been observed at the same time.
The discovery was made possible thanks to observations made with Lofar (LOw Frequency ARray), the largest low-frequency radio telescope in the world, which is capable of capturing the radiation produced by the oldest electrons that we can pick up. This powerful tool of the latest generation (the result of a great collaboration between nine European countries) has allowed scholars to go back in time to more than 100 million years ago and reconstruct the activity of the black hole at the center of Nest200047.
"Our observations show how these black hole-accelerated gas bubbles expand and transform over time, creating spectacular mushroom-shaped structures, rings and filaments, similar to those created by a powerful volcanic eruption on earth," says the former. author of the study Marisa Brienza, researcher at the University of Bologna and associated with Inaf.
The results obtained show that the black hole's activity has a strong impact even on scales 100 times larger than the host galaxy and that it can last up to hundreds of millions of years.
