An article published in the journal “Nature” reports the observation of very strong winds coming from the supermassive black hole at the center of the galaxy Cosmos-11142 which inhibited star formation within it. A team of researchers led by Professor Sirio Belli of the University of Bologna, Italy, used the James Webb Space Telescope to detect the movement of cold neutral gas pushed at such a speed that it swept away the gas in the galaxy and thus prevented the formation of new stars. This is the first evidence of how a supermassive black hole can have that effect on a galaxy.
The image (Courtesy Belli et al., 2023. All rights reserved) shows a spectroscopic observation conducted with the James Webb Space Telescope’s Near Infrared Spectrograph (NIRSpec) instrument of the galaxy Cosmos-11142 centered on the oxygen emission line doubly ionized.
For years, astronomers have been studying the effects of the activity of supermassive black holes on the galaxies that host them. In particular, an active galactic nucleus powered by a supermassive black hole surrounded by large amounts of material can have a remarkable influence. Observations indicate that in primordial galaxies there were periods of intense star formation, followed by a sort of almost complete shutdown, called quenching in jargon.
Theoretical models indicate that supermassive black holes can generate winds strong enough to push gas outwards, but so far, observations only showed galactic winds that are much weaker than predicted. That’s because so far, the available instruments were only able to detect ionized gas, which is warm, but not neutral gas, which is cold. Things changed with the James Webb Space Telescope.
The galaxy Cosmos-11142 was observed during the Blue Jay program, during the first cycle of the James Webb Space Telescope’s observations. In particular, the NIRSpec instrument was used to detect neutral gas as it was pushed away by the activity of the supermassive black hole about ten billion years ago.
The result is that the outflow of cold, neutral gas is one hundred times greater than the ionized gas that could previously be detected. Essentially, in the past, astronomers could only see the equivalent of the tip of the iceberg. The James Webb Space Telescope has once again proved its power and sensitivity, in this case, allowing to see the equivalent of the entire iceberg.
According to the reconstruction of Sirio Belli’s team, the galaxy Cosmos-11142 had a period of the type called starburst in jargon, with a remarkable star formation activity that at a certain point stopped almost completely. The researchers plan to study other primordial galaxies with the James Webb Space Telescope to examine other active galactic nuclei for winds formed by neutral gas. Confirming the observations already obtained would constitute another step forward in understanding the influence of supermassive black holes on the galaxies that host them.
