Back from the dead, a black hole is erupting after a 100-million-year hiatus

"Inside an incredibly bright cluster of galaxies, a long-dormant supermassive black hole has come back to life. Radio images captured a one-million-light-year-long stream of star-forming particles and gas emanating from the black hole at the center of the galaxy J1007+3540which apparently is erupting for the first time in about 100 million years. Although some restarted' radio galaxies are known in the literature, J1007+3540 stands out, says lead study author Shobha Kumari of Midnapore City College in India. The result recently appeared in the Monthly Notices of the Royal Astronomical Society."

"J1007+3540 is an uncommonly large example of an episodic galaxy, wherein a central supermassive black hole only intermittently emits prominent jets of particles and gas, almost as if an astrophysical on-off switch was flipped. Researchers say the information they gain from the eruption of this cosmic volcano could help them better understand episodic galaxies' structures, evolution and influence on their surroundings."

"Ejected jets are a consistent but not ubiquitous feature of the supermassive black holes at the hearts of galaxies, which, when erupting, are also called active galactic nuclei (AGNs). Many AGNs are thought to be episodic, ebbing as they exhaust surrounding reservoirs of gas, only to surge again when more material drifts within reach. This cycle elapses across thousands of yearsglacially slow to us but almost instantaneous on cosmic scales. That makes episodic activity and the on-off transition difficult to catch as it occurs. Rather than attempting to observe the changes themselves, scientists often analyze the structures within galaxies they think arise from a central black hole's episodic ou"

J1007+3540 resides in a very bright galaxy cluster and contains a supermassive black hole that had been dormant for roughly 100 million years before restarting. The black hole is producing a one‑million‑light‑year radio stream composed of particles and gas that is associated with star formation. The galaxy exemplifies an episodic radio galaxy whose central black hole emits jets intermittently, resembling an astrophysical on‑off switch. Episodic jet activity arises as black holes exhaust and later reacquire surrounding gas reservoirs. Jet cycles span thousands of years, making transitions hard to observe directly, so structures left in galaxies are analyzed to infer episodic behavior and its impact on galactic evolution and surroundings.

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