After 100 million years it woke up. Strange behavior of a black hole

At the heart of an extremely bright galaxy cluster, astronomers have observed what looks like a cosmic volcano awakening after 100 million years of sleep. The supermassive black hole in the J1007+3540 galaxy – previously thought to be extinct – has once again begun spewing a gigantic stream of particles and gas into space. It extends for over a million light years.

This extraordinary phenomenon makes J1007+3540 one of the most spectacular examples of the so-called episodic galaxies. These are galaxies in which the central black hole acts like a cosmic switch – it remains silent for a long time, then suddenly explodes with powerful streams of material. Scientists hope that observing this “reboot” will allow us to better understand how such galaxies evolve and how they influence their surroundings.

The ejected jets (streams of matter) are the result of the activity of active galactic nuclei (AGN). Many of them operate in an episodic mode – they weaken when they exhaust nearby gas and revive when there is new material to “consume”. This cycle lasts thousands of years. Of course, on a cosmic scale it is only the blink of an eye, but for astronomers it obviously poses a significant observational challenge.

That is why the J1007+3540 radio images taken by the LOFAR radio telescope in the Netherlands and the Giant Meterwave Radio Telescope in India are so valuable. They captured two phases of a black hole’s life simultaneously: a) a freshly born, bright jet and b) extensive remnants of previous eruptions. In other galaxies, such structures are usually harder to read, but here they are especially clear.

One of the most intriguing features is a faint, jagged tail of old material that stretches far into intergalactic space. Its shape shows how new AGN eruptions interact with the gas filling the entire galaxy cluster, the so-called intercluster center (ICM). This is where the black hole’s jet is constantly being formed, slowed down, and deformed by the gas it encounters.

Astronomers emphasize that the relationship between jets and their environment is extremely dynamic – it is not a stream flowing freely through a void, but a structure constantly formed by the environment in which it moves. And such interactions may determine whether new generations of stars will be created in the galaxy, or whether star formation processes will be inhibited.