accretion

A 2023 study in The Astrophysical Journal revealed that black holes which suck up gases — forming what's known as accretion disks — do so in a manner of mere months, which is extremely rapid on an interstellar timescale, as well as 10 to 100 times faster than scientists previously believed.

The researchers led by Northwestern University's Nick Kaaz, a graduate student in astronomy, used computer simulations to determine that the black hole causes rotations which warp the accretion disk in such a way that the gas actually starts caving in on itself.

Eventually the entire accretion disk is torn in half, with the black hole first consuming the inner disc and then the outer one.

They can consume gas from their host galaxies in a process called accretion, and they can also merge with each other when two galaxies collide.

When there isn’t enough gas available for supermassive black holes to grow by accretion, the only way for them to get larger is through mergers.