Supermassive black holes may have a completely unexpected cosmic delivery service supplying them with gas and S dust to feast on. This could result in the cosmic titans feeding much faster than scientists had expected, gorging themselves over a period of months rather than hundreds or even thousands of years. Supermassive black holes with masses of millions or even billions of times that of the Sun are believed to dwell at the hearts of most galaxies, and when they’re surrounded by vast plates of gas and dust called accretion discs, they power quasars.
These new findings about black hole feeding rates could help shed light on how these supermassive voids gobble up surrounding material and how that process influences the evolution of galaxies. The research is the result of high-resolution 3D simulations performed by a team of scientists who set out to understand black hole dynamics and ended up capturing a surprisingly quick feeding rate of these elusive phenomena. This increased feeding rate may be supported by realworld observations of quasars as well, some of which brighten and fade with a timescale of months. “How gas gets to a black hole to feed it is the central question in accretion-disc physics,” Nick Kaaz, team leader and an astronomer at Northwestern University, said. “If you know how that happens, it will tell you how long the disc lasts, how bright it is and what the light should look like when we observe it with telescopes.”
Supermassive black holes are so massive that when they spin they drag the very fabric of space-time along with them – a phenomenon called frame dragging or the Lense-Thirring effect. 3D simulations performed using the Summit supercomputer at Oak Ridge National Laboratory showed that this twisting of space rips up accretion discs and causes them to split into inner and outer ‘subdiscs’. Supermassive black holes treat the inner disc as an appetiser, in a way, because they start their dinner by devouring gas and dust found there first. As this is happening, matter from the outer disc filters in, eventually filling in gaps left behind by the black hole devouring the inner disc. This filled-in disc then becomes the main course, allowing the feeding process to start all over again.