A joint research team from Raman Research Institute (RRI), an autonomous institute of the Department of Science and Technology, and Arizona State University has discovered a mechanism by which supermassive black holes at galactic centers influence the circumgalactic medium (CGM), the diffuse gaseous reservoir extending 10-20 times beyond the galactic disk that provides fuel for star formation. The research, published in The Astrophysical Journal Letters (DOI 10.3847/2041-8213/ae9cbd), demonstrates that jets of hot plasma emitted by black holes create a jerk when they first encounter the CGM, energizing and ionizing the gas along their specific path rather than affecting gas equally in all directions.
The team detected strong ionization signals specifically along the direction of the jet, with the strongest signals occurring at two locations: at the edge of the stellar disk where the jet first encounters the CGM, and at the CGM's outer boundary where the slowed jet interacts with the gas. This energy deposition prevents the gas from cooling and clumping together to form stars, effectively suppressing star formation and making galaxies "quiet and passive." The research provides evidence for how relatively tiny black holes (solar system-sized compared to galaxies hosting 100 billion stellar systems) can exert influence far beyond their immediate vicinity, shaping galactic evolution by governing star formation rates through this jet-mediated mechanism.