Back from the Dead: Restarted Black Hole activity discovered in a Giant Radio Galaxy under extreme cosmic pressure

This research was part of a global effort, involving experts from India and Poland. Apart from the lead authors, Dr. Surajit Paul from the Manipal Centre for Natural Sciences in India and Dr. Marek Jamrozy, of Jagiellonian University in Poland also played an important part in this research. Their findings were recently published in the Monthly Notices of the Royal Astronomical Society, one of the leading astronomy journals.

“Our research shows how extreme cosmic pressure in a galaxy cluster is physically sculpting these fresh energy gets,” Dr Pal ssaid. Astronomers explained that this galaxy is very gigantic, spanning over 3 million light-years.

“To put that in perspective, it is 50 times wider than our own Milky Way. However, life for this galaxy is far from peaceful. It sits in the middle of a “galaxy cluster,” a crowded neighborhood filled with searing-hot gas. This gas creates immense pressure, acting like a heavy atmosphere that tries to crush everything inside it,” Dr Pal added.

By studying the radio waves emitted by this galaxy, scientists said that the images reveal a “double-double” structure—a pair of bright, fresh energy jets nested inside much older, fainter ones—which proves the central black hole has recently re-ignited after a long period of silence. As these new jets blast outward, they are locked in a struggle with their surroundings; the intense pressure from the hot gas in the galaxy cluster is actually pushing the jet’s plasma sideways, creating striking curved shapes.

Using the unique low-frequency capabilities of the upgraded GMRT (operated by the National Centre for Radio Astrophysics -Tata Institute of Fundamental Research – Pune) the team witnessed a monster black hole `waking up’ after a 100-million year silence. (Special Arrangement)

“This hostile environment has not only distorted the ancient plasma but is also stripping material away from the galaxy as it moves, leaving behind a wispy, millions-of-years-old trail known as a “galactic wake”. This galaxy isn’t just growing; it’s fighting for survival,” Dr Pal further explained. It acts as a natural laboratory for scientists to see how black holes turn on and off, and how they shape the universe around them. Astronomers said that it was `a violent, beautiful “tug-of-war” between the power of a black hole and the crushing weight of deep space.’

The low-frequency Band 3 (250–500 MHz) image of J1007+3540 using uGMRT helped to trace the extended diffuse emission,showing the large-scale tail as well as the inner episodic jet and associated distorted outflow structures. The uGMRT image was further used to study the spectral properties of the source. In particular, the spatial distribution of the spectral index for the different parts of the structure helped to understand the ageing nature of the radio emission in the particular region.

By studying this unique system, scientists can finally observe the full life cycle of supermassive black holes—from how they power up to how they fall silent and eventually “wake up” again.