How massive black holes ‘feed’ on intergalactic gas

Research led by the University of Southampton has revealed how supermassive black holes feed on gas clouds that come from other galaxies hundreds of thousands of light-years away.

The international team of scientists has shown that there is a crucial link between the interaction of neighboring galaxies and the enormous amount of gas needed to “feed” these gigantic superdense space phenomena, according to the article published in Nature Astronomy. A black hole can be created when a star collapses, squeezing matter into a relatively small space. This increases the force of gravity to a point where nothing can escape, not even light, hence the name. Some black holes are gigantic, with masses millions of times that of our sun, and they emit enormous amounts of energy. They are known as ‘supermassive black holes’ and how they form or get enough fuel to function is still a mystery.

Dr. Sandra Raimundo, astrophysicist and principal investigator at the University of Southampton, explains in a statement that “supermassive black holes fuel their activity, in part, by the gradual buildup of gas from the surrounding environment. They can cause centers of Galaxies shine brighter when they capture gas, and it is thought that this process can greatly influence what galaxies look like today.” “How ANSMs get enough fuel to sustain their activity and growth continues to baffle astronomers, but the work we’ve done is a step forward in understanding it,” he stresses. The Southampton scientist, in collaboration with researchers from the Universities of Copenhagen (Denmark) and California (United States), used data from the Anglo-Australian 4-meter telescope in New South Wales (Australia) to study the orbits of gas and the stars in a large sample of more than 3,000 galaxies. They identified those with the presence of what is known as “misaligned” gas, that is, gas that rotates in a different direction from that of the stars in the galaxy, a sign of past galactic interaction. Next, they found that galaxies with misaligned gas had a higher fraction of active supermassive black holes.

The results showed a clear relationship between misaligned gas and supermassive black hole activity, suggesting that gas transfers where two galaxies meet, meanders vast distances through space, and then succumbs to the black hole’s enormous gravitational forces. supermassive, dragged along and gobbled up as a vital source of fuel. Astronomers have long suspected that a merger with another galaxy could provide this source of gas, but direct evidence for it has been elusive. Dr. Raimundo explains that “the work shows that the presence of misaligned gas with respect to stars is associated with an increase in the fraction of active supermassive black holes. Since misaligned gas is a clear sign of a past interaction between two galaxies – “He continues,” our work demonstrates that interactions between galaxies provide fuel to power active supermassive black holes.” “This is the first time that a direct connection between the formation and presence of misaligned gas and the feeding of active supermassive black holes has been observed,” he adds. For her part, Dr. Marianne Vestergaard, co-author of the study, highlights that “the exciting thing about these observations is that we can now, for the first time, identify the captured gas and trace it to the center, where the black hole devours it.”