Supermassive black holes could cause the death of galaxies

Supermassive black holes may influence the formation of galactic stars and cause the death of galaxies, a new study claims. Recent research has shed light on how the birth and death of a galaxy, also known as the galactic cycle, occurs. The study reveals that the mass of a supermassive black hole can have a significant impact on the amount of cold gas available in the host galaxy, a key component for star formation. The connection between these black holes and the suppression of star formation provides a clearer understanding of how galaxies transition from active star-forming regions to “quiet” regions.

Black holes and galactic death

It is now believed that supermassive black holes, which are located at the centers of large galaxies, play a crucial role in suppressing star formation. Scientists have observed that galaxies with more massive black holes tend to have less cold gas. This gas is essential for the formation of new stars, and its depletion can lead to a galaxy transitioning to a more passive state, where star formation slows down or stops significantly. Tao Wang and his team from Nanjing University have linked the mass of these black holes to the reduced gas content in their host galaxies, in a study published in the journal Nature.

Evidence and theories

The research indicates that more massive black holes are associated with lower amounts of cold atomic hydrogen gas. This gas, which is crucial for star formation, appears to decrease as the mass of the black hole increases. This phenomenon is consistent with observations of passive galaxies, which generally show reduced star formation activity and gas reservoirs. The study suggests that supermassive black holes may be ejecting this gas from galaxies or preventing them from acquiring new gas from intergalactic space.

Future research directions

The findings challenge previous theories that did not definitively link black hole mass to the decrease in star-forming gas. More research is needed to investigate the mechanisms by which black holes influence their host galaxies. The team plans to investigate how dense molecular gas, another crucial component for star formation, correlates with black hole mass. This future work, possibly using the ALMA observatory, is intended to provide deeper insights into the impact of black holes on galaxy evolution.

By investigating the relationship between supermassive black holes and gas reservoirs in galaxies, this research opens new avenues for understanding how galaxies evolve and stop forming new stars.