NASA Spots Supermassive Black Hole Ejecting Stream of Super Fast Gas

Scientists have made a surprising discovery when it comes to a supermassive black hole at the heart of the galaxy, NGC 5548. They've found that this black hole is emitting a stream of rapidly flowing gas that blocks about 90 percent of its emitted X-rays, an extremely unusual behavior that's telling scientists a bit more about how supermassive black holes interact with their host galaxies.

The galaxy NGC 5548 is located about 244.6 million light-years from Earth. Using NASA's Hubble Space Telescope and data from other spacecraft, the scientists combined their findings. In the end, the researchers noticed the unusual behavior of the supermassive black hole at its center.

"The data represented dramatic changes since the last observation with Hubble in 2011," said Gerard Kriss, one of the researchers, in a news release. "I saw signatures of much colder gas than was present before, indicating that the wind had cooled down due to a significant decrease in X-ray radiation from the galaxy's nucleus."

Supermassive black holes in the center of active galaxies usually expel large amount of matter through powerful winds of ionized gas. For example, the persistent wind of NGC 5548 reaches velocities that exceed 621 miles a second. Yet it seems as if a new wind has arisen that's far stronger and more powerful than the persistent one.

"These new winds reach speeds of up to 3,107 miles per second, but is much closer to the nucleus than the persistent wind," said Jelle Kaastra, one of the researchers, in a news release. "The new gas outflow blocks 90 percent of the low-energy X-rays that come from very close to the black hole, and it obscures up to a third of the region that emits the ultraviolet radiation at a few light-days distance from the black hole."

It looks as if the shielding in NGC 5548 has been occurring for at least three years. However, it's only just crossed the line of sight for astronomers.

"There are other galaxies with similar streams of gas flowing outward from the direction of its central black hole, but we've never before found evidence that a stream of gas changed its position as dramatically as this one has," said Kriss in a news release. "This is the first time we've seen a stream like this move into our line of sight. We got lucky."

The findings are published in the journal Science Express.