14 DAY TRIAL // A new scientific study on some of the Universe's largest black holes has revealed a surprising feeding pattern that astrophysicists were not aware of until now. It would appear that this dark behemoths can grow by consuming small amounts of gas from their surroundings, rather than gorging themselves.
For many years, scientific models of the black holes have shown that those of the supermassive variety tend to consume vast amounts of matter at all times, including cosmic dust, hydrogen gas, stars, and planetary systems.
But the new investigation paints a somewhat different picture of these giants, while at the same time providing essential mission clues of how black holes throughout the Cosmos feed and grow.
The scientists behind the new investigation were able to discover the new feeding behavior in supermassive black holes located at the cores of a specific type of galaxies, which makes up about half of all such structures in the known Universe.
These “skinny” formations feature no central bulges, such as the Milky Way does. It is very common for spiral galaxies to contain such structures, which are made up by agglomerations of stars and nebulae around the central dark behemoth.
But the new data indicate that things are different in galaxies with no bulges. Black holes here can feed and grow on small bits of matter, rather than large chunks, as is the norm. This conclusion was drawn after researchers looked at what matter these objects had available to feed on.
“We now strongly suspect that there is an alternative mode of black hole growth,” explains John Kormendy, who holds an appointment as an astronomy researcher at the University of Texas in Austin.
“We could reasonably call this second mode 'nibbling' – the black hole just eats a bit of gas that happens to come too close because of random local processes like gas cloud collisions or just because gas happens to pass by the black hole,” he adds.
In the past, experts believed that galaxies and black holes grew through co-evolution, where the size of the dark behemoth was directly related to that of its host galaxy, its bulge and its galactic disk.
But this is not true in bulge-free galaxies, where black holes “never produces enough energy to influence the overall host galaxy,” Kormendy explains.
“Hence there is no co-evolution – the black hole growth and any evolution of the galaxy happen independently of each other,” the researcher adds, quoted by Space.
“Only in the past few years have we been made aware of how flat many galaxies are,” Princeton University physicist James Peebles tells Space in an interview. He was not involved in the new study.
“They're a real challenge to our standard ideas of galaxy formation, because computer simulations suggest that any flat galaxies produced early on should soon get wiped out during galactic mergers,” he explains.
“These findings could at least reveal details on how they evolve. Understanding their black holes could have something to do with the puzzle,” he adds.
Details of the new research, which was authored by Kormendy and colleagues, appear in the January 20 issue of the esteemed scientific publication Nature.