A new study by Indian astronomers has found that supermassive black holes and their powerful jets work together to expel gas from the centers of galaxies, effectively halting the formation of new stars and shaping the course of galactic evolution.
The research, carried out by scientists at the Indian Institute of Astrophysics (IIA)—an autonomous institute under the Department of Science and Technology (DST)—provides fresh insight into how radiation and high-speed radio jets near black holes act in tandem to regulate star formation.
Using archival data from international observatories, including the Sloan Digital Sky Survey (SDSS) and the Very Large Array (VLA) in the U.S., the team examined more than 500 nearby galaxies that host active galactic nuclei (AGN)—the extremely bright cores powered by matter falling into supermassive black holes.
“We found that warm ionized gas outflows are common in AGN. While radiation from the black hole is the primary driver, galaxies with radio jets exhibit much faster and more energetic outflows,” said Payel Nandi, lead author of the study and a Ph.D. student at IIA.
The study revealed that these high-velocity gas streams—moving at speeds of up to 2,000 kilometers per second—are more than twice as frequent in galaxies with radio emissions (56%) compared to those without (25%). Such powerful winds can escape a galaxy’s gravitational pull, playing a crucial role in shutting down star formation in its central regions.
“This research underscores the importance of combining data across multiple wavelengths to fully understand galaxy evolution,” said Dr. C. S. Stalin, co-author and faculty member at IIA.
The team also observed a strong link between the energy of the outflows and the brightness of the central black hole. The presence of radio jets—narrow beams of high-speed, charged particles—was found to enhance these outflows further, acting as an amplifier.
“These results mark an important step toward unraveling the complex connections between supermassive black holes, radio jets, star formation, and galaxy evolution,” said Dhruba J. Saikia, co-author and researcher at the Inter-University Centre for Astronomy and Astrophysics.
By studying stellar populations and infrared color data, the researchers confirmed that black hole activity, rather than new star formation, drives these massive winds. This phenomenon, known as negative AGN feedback, suppresses star formation in galactic cores and could explain why some galaxies have extremely low rates of star birth.
Published in The Astrophysical Journal, the findings represent a significant leap in understanding how black holes and their energetic outflows shape the life cycles of galaxies across the universe.
