Supermassive Black Hole Caught Rejecting Material

New images of the supermassive black hole located at the center of the Milky Way reveals why the material surrounding it emits very little in the way of X-rays.

Taken using NASA's Chandra X-ray Observatory, the images reveal that more than 99 percent of the gas that comes within the grasp of the black hole, known as Sagittarius A*, is rejected before it is able to reach the point of no return, also known as the event horizon, causing weak X-ray emissions.

The study's results come from one of the longest observation campaigns ever performed using Chandra, having been collected over a five week period. During this time, the researchers captured unusually detailed X-ray images and energy signatures of super-heated gas surrounding the black hole.

"We think most large galaxies have a supermassive black hole at their center, but they are too far away for us to study how matter flows near it," said Q. Daniel Wang of the University of Massachusetts in Amherst, who led the study published in the journal Science. "Sgr A* is one of very few black holes close enough for us to actually witness this process."

Co-author Sera Markoff of the University of Amsterdam said the images were some of "the coolest I've ever seen."

"We're watching Sgr A* capture hot gas ejected by nearby stars, and funnel it in towards its event horizon," Markoff explained.

In order to take the plunge over the event horizon, the material captured by a black hole must lose heat and momentum, which is exactly what the ejection of matter allows for, the scientists explain.

"Most of the gas must be thrown out so that a small amount can reach the black hole," said Feng Yuan of Shanghai Astronomical Observatory in China, the study's co-author. "Contrary to what some people think, black holes do not actually devour everything that's pulled towards them. Sgr A* is apparently finding much of its food hard to swallow."