Supermassive Black Hole Dines on Cold Gas

Monday, 13 June 2016 - 2:52PM
Monday, 13 June 2016 - 2:52PM
Supermassive Black Hole Dines on Cold Gas
Black holes have to eat too, apparently. For the first time, astronomers have captured an amazing phenomenon in which supermassive black holes feed on clouds of cold gas.

Up until now, scientists had imagined that the process of fueling a black hole, known as accretion, was a relatively simple one.

Opening quote
"The simple model of black hole accretion consists of a black hole surrounded by a sphere of hot gas and that gas accelerates smoothly onto the black hole, and everything's simple, mathematically," explains Michael McDonald, assistant professor of physics at MIT.
Closing quote


But now, astronomers have detected huge clouds of cold, clumpy gas streaming towards a supermassive black hole at the center of a massive galaxy cluster. The clouds are traveling at 800,000 miles per hour, and may only be 150 light years away from the edge of the black hole - almost certain to fall in and become its fodder. These observations are the first direct pieces of evidence to support the hypothesis that black holes feed on clouds of cold gas.

Opening quote
"This is the most compelling evidence that this process is not smooth, simple, and clean, but actually quite chaotic and clumpy," says McDonald.
Closing quote


McDonald headed a team of researchers who originally wanted to get a sense for how many stars the Abell 2597 Cluster (some tens of thousands of light years across) was producing, so they mapped all the cold gas within the cluster using the ALMA telescopes. It is the collapse of the cold gas that creates new stars, but instead, this cold gas cooled and condensed, forming clumps. 

At the very center of the Abell Cluster, just at the edge of the cluster's supermassive black hole, the researchers discovered something unexpected - the shadows of three very cold, clumpy gas clouds. The shadows were being cast against bright jets of material spewing from the black hole, suggesting that these clouds were very close to being eaten by the black hole. "We got very lucky," says McDonald," We could probably look at 100 galaxies like this and not see what we saw just by chance."

Given these new observations, McDonald says that black holes probably have two different ways of feeding. The most common way is a slow graze on hot, diffused gas, but once in a while they may quickly swallow up clumps of cold gas as it comes nearby.

Opening quote
"This diffuse, hot gas is available to the black hole at a low level all the time, and you can have a steady trickle of it going in. Every now and then, you can have a rainstorm with all these droplets of cold gas, and for a short amount of time, the black hole's eating very quickly. So the idea that there are these two dinner modes for black holes is a pretty nice result."
Closing quote




Science
NASA

Load Comments