NASA observed a black hole that was eclipsed by a fast-moving gas streamliner. The findings suggest super-strong winds have an effect of black hole growth and its surrounding galaxy.
The researchers noticed a clumpy gas stream flowing out of a supermassive black hole at the heart of the galaxy NGC 5548; it blocked 90 percent of the black hole's emitted X-rays, a Hubble news release reported.The rare streamer is long-lived, but was just recently spotted by NASA's Hubble telescope. The finding provides new clues into the behavior of black holes that lie at the center of galaxies.
"There are other galaxies that show gas streams near a black hole, but they haven't changed their position as dramatically," Gerard Kriss of the Space Telescope Science Institute (STScI), said in the news release. "This is the first time we've seen a stream like this move into the line of sight. We just happened to get lucky."
The finding represents the first direct evidence of a predicted "shielding process" that accelerates gas streams and winds. These winds can be so strong they can blow away gas that would have fallen into the black hole under different circumstances. The findings suggest black hole winds can regulate the growth of both the black hole and its galaxy.
"There were dramatic changes since the last observation with Hubble in 2011. I saw signatures of much colder gas than were present before, indicating that the wind had cooled down due to a strong decrease of ionizing X-ray radiation from the nucleus," Kriss said.
After looking at data from six observatories the researchers were able to get a glimpse of the big picture. Supermassive black holes in the heart of active galaxies release powerful winds made up of ionized gas. Persistent wind of NGC 5548 reached velocities of over 621 miles (about 1,000 kilometers) per second, but the new winds that have arisen are much faster.
"The new wind reaches speeds of up to 3,107 miles (5,000 kilometers) per second but is much closer to the nucleus than the persistent wind," Jelle Kaastra of the SRON Netherlands Institute for Space Research said. "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."
