A new method for measuring the spin of supermassive black holes could help astronomers better understand how the black holes drive the growth of galaxies.
A team of astronomers from the University of Durham have been examining a supermassive black hole with a mass more than 10 million times that of our sun. The black hole is the glue that hold an entire galaxy together, some 500 million light years from our planet. The astronomers observed the black hole feeding off of the disk of matter that surrounds it and fuels its growth.
The team was able to deduce the spin of the black hole by looking at optical, x-ray and ultraviolet images of the disk around it. The faster the black hole spins, they realized, the more it would draw in the material in the disk, thus bringing it closer. In other words, by measuring the distance between the black hole and the disk, they could find the spin.
The scientists say that understanding black hole spin can be important to understanding how galaxies grow over billions of years. Black holes exist at the center of almost every galaxy, including our own. They frequently spit out high-energy jets of super hot particles that prevent the outermost gases in the galaxy from cooling and forming stars. We still don’t know why they do this, but the astronomers at Durham believe the spin is closely connected to the phenomenon.
Black holes hold galaxies together. Powerful stuff
Profesor Chris Done is lead researcher on the project and puts the enormous power of black holes into context that’s easier to understand: “We know the black hole in the center of each galaxy is linked to the galaxy as a whole, which is strange because black holes are tiny in relation to the size of a galaxy. This would be like something the size of a large boulder (10m), influencing something the size of Earth.”