The activity of supermassive black holes has slowed down the growth of galaxies.

The Protocluster Spiders (PKS 1138-262) formed in the relatively early universe: astronomers observe this object as it was over 10 billion years ago. Although the cluster has been well-studied, it still harbors many mysteries — previously, two research teams discovered 41 new galaxies within Spiders.

To understand why some inhabitants of this ancient cluster are predominantly made up of old stars, astronomers investigated star formation and the activity of supermassive black holes at the centers of galaxies. The findings of this research, presented in the journal Monthly Notices of the Royal Astronomical Society, revealed that in galaxies with active supermassive black holes, star formation was significantly lower than expected.

Using the James Webb Space Telescope (and its onboard infrared camera NIRcam), the team of scientists obtained a map of massive galaxies in the Protocluster Spiders (previously, these objects were identified using the Subaru MOIRCS camera, but a connection between star formation and black hole activity could not be established at that time) and focused on comparing two groups of massive galaxies: in the first group, the star formation process continued, while in the second, it did not.

In galaxies where new stars were not forming, sources of X-ray emission were identified, indicating the activity of central supermassive black holes. The results also showed that in the first group of galaxies, stars were forming in disks extending thousands of light-years, whereas the stellar disks in the second group were less pronounced (concentrated in the central regions).

The research team led by astronomer Rhythm Shimakawa from Waseda University (Japan) has been studying Spiders for over 10 years and concluded that the energy released by supermassive black holes during accretion likely suppressed the birth of new stars and gradually transformed "star factories" into more "passive" elliptical galaxies (thereby influencing their evolution).

New data supports the long-standing hypothesis regarding the ability of central supermassive black holes to "turn off" star formation and create massive elliptical galaxies. In the future, these findings will help to understand how galaxies form and "fade" across the universe, and further observations will provide more insights into the mechanisms of ancient cosmic structures' formation and their evolution.