Supermassive Black Hole Reawakens After 100-Million-Year Nap, Jets Interact with Cosmic Gas

A supermassive black hole at the center of galaxy J1007+3540 has reignited after a 100-million-year dormancy, as revealed by radio emissions.

The galaxy exhibits two distinct jet structures: older plasma lobes (240 million years) and younger jets (140 million years), providing observational evidence of episodic active galactic nucleus (AGN) behavior.

Shobha Kumari, co-author of the study, described the phenomenon as "watching a cosmic volcano erupt again after ages of calm — except this one is big enough to carve out structures stretching nearly a million light-years across space." The intracluster medium — superheated gas between galaxies — bends and distorts the jets, creating squished and kinked shapes that reveal how cosmic environments shape AGN activity.

The research team used the Low-Frequency Array (LOFAR) radio telescope network to identify over 20 galaxy clusters with irregular jet structures. Surajit Pal, another co-author, noted that J1007+3540 is "one of the clearest and most spectacular examples of episodic AGN with jet-cluster interaction."

The study, published January 15, 2024, in Monthly Notices of the Royal Astronomical Society, highlights the critical role of the intracluster medium in shaping jet morphology and AGN lifecycles.

While the 240-million-year-old lobes and 140-million-year-old jets confirm episodic AGN behavior, the team acknowledges limitations in resolving shorter timescale variations. Further observations are needed to determine how frequently such reactivations occur and whether they correlate with galactic mergers or other external triggers.