New JWST observations show black holes rapidly halt star formation in massive galaxies

New research published in nature New observations from the James Webb Space Telescope (JWST) are presented, which show that black holes rapidly prevent star formation in massive galaxies by explosively removing large amounts of gas.

The international team found that more than 90% of the galactic wind is made of neutral gas and was therefore virtually invisible in previous studies. This work is the first direct confirmation that supermassive black holes can shut down galaxies.

The difference between this new study and previous work is the type of gas observed: So far, only ionized gas, which is warm, has been detected; whereas JWST is also able to detect cold, neutral gas.

Dr Rebecca Davis from Swinburne University of Technology’s Center for Astrophysics and Supercomputing led the Australian team behind the discovery and helped discover a powerful black hole in a distant, massive galaxy with very low levels of star formation Driven exodus.

“Outflows remove gas faster than the gas is converted into stars, suggesting that outflows may have a very significant impact on the evolution of galaxies. Our findings provide new evidence that black hole-driven outflows can quickly shut down or ‘Quinking’ star formation in massive galaxies.

When star formation ceases, it means that the galaxy has stopped forming stars. It represents the transition between a galaxy that is actively forming stars, causing them to grow and change, and a galaxy that is “dead” and stationary. Therefore, quenching is a fundamental process in the life cycle of galaxies. However, astronomers still don’t understand in detail what causes galaxies to stop forming stars.

Dr Davies worked with internationally renowned researchers, notably lead author Sirio Bailey of the University of Bologna, to study a galaxy so far away from Earth that its light takes more than 10 billion years to reach us.

Active galactic nucleus (AGN) supermassive black holes that consume large amounts of gas can drive galactic outflows. The most powerful AGNs drive very large outflows, which may clear all the gas from their host galaxies in a relatively “short” time and cause star formation to cease.

“JWST allows us to observe the cooler neutral gas phase of normal AGN-driven outflows in distant galaxies. In the galaxies studied, we found that the neutral phase outflow rate is approximately 100 times greater than the outflow rate in the ionized phase, thus revealing Many previously unseen outflow masses.

Dr Davis said JWST could be used to detect a much larger proportion of the outflow, whereas previous observations of ionized gas could only detect around 1%.

“Before JWST, we had only scratched the tip of the iceberg when it came to outflows.”

The team is excited about what they might discover in the future when they analyze more galaxies.