How Are Supermassive Black Holes Formed?
- Author: Arturo Norris Mar 17, 2017,
Mar 17, 2017, 19:23
Knowing this, we can imagine that supermassive black holes start out small and then gradually become more massive by ingesting more dust, gas, hamburgers or whatever comes across the stellar-grade black hole's insatiable appetite. No one yet understands exactly how nature has managed to compress so much matter into such small spaces. Such an environment wouldn't have allowed for the formation of supermassive black holes, as the stars were created far enough to escape being absorbed.
Therefore, a prerequisite for the formation of supermassive black holes under this theory is very inefficient cooling, which in the very early universe could only be achieved by emission of molecular hydrogen. Given the 13.8 billion years that have passed since the Big Bang, it may be enough time for supermassive black holes to grow to their huge sizes, but how then do we explain that some of them formed less than 800 million years after the universe came into existence? "A few hundred-million years later, it has grown into a billion-solar-mass supermassive black hole".
Dr Regan's modelling, surmises that when proto-galaxies are in close proximity, the powerful radiation field of one proto-galaxy, sterilises the other, thus disabling its ability to form stars.
It's no secret that supermassive black holes are heartless beasts: These objects of vast gravity that let nothing escape, not even light, have fascinated astronomers since the early 20th century.
Black holes grow rapidly in the center of the galaxy that hosts them only if another galaxy nearby emits radiation.
The theory of how supermassive black holes grew so early may not be as far-fetched, as the latest simulations show the radiation-emitting galaxies don't have to be as large as previously estimated. This is the moment when the black hole is formed.
"We wanted to explain how they seemed to grow nearly instantly, how they got so big so quickly", said Dr John Regan, who is based at Dublin City University's school of mathematical sciences.
"The collapse of the galaxy and the formation of a million-solar-mass black hole takes 100,000 years - a blip in cosmic time", study co-author Zoltan Haiman, an astronomy professor at Columbia University, said in a statement. "This is much faster than we expected". The researchers also considered the effects on the process of chemistry, radiation, gravity, and fluid dynamics.
It's an important requirement to create the right conditions for supermassive black holes to thrive. The team is already planning to follow up this research with a study on how the merging of millions of black holes and stars could have formed ancient giants.
"Understanding how supermassive black holes form tells us how galaxies, including our own, form and evolve, and ultimately, tells us more about the universe in which we live", said Regan. The other authors are Eli Visbal, now a postdoctoral researcher at the Simons Foundation Flatiron Institute; Peter Johansson, an astrophysics professor at the University of Helsinki; and Greg Bryan, an astronomy professor at Columbia and the Flatiron Institute.