Astronomers this week have revealed the confirmation that the black hole at the center of our galaxy is ejecting a stream of high-energy particles. The new findings have been published in The Astrophysical Journal.
Researchers for some time have assumed that our Milky Way galaxy has a jet of particles spouting from its center, much like other galaxies similar to it. It is hypothesized that these types of jets are formed as material orbiting a black hole is forced outwards. Observations of the Milky Way's supermassive black hole, named Sagittarius A*, have come up short in the past. These new findings confirm both the existence of the particle jet and its intensity, which is weak compared to other jets seen in the universe.
"For decades astronomers have looked for a jet associated with the Milky Way's black hole," said Zhiyuan Li, lead author of a study and an astronomer at Nanjing University. "Our new observations make the strongest case yet for such a jet."
Li and her colleagues were able to discover the jet using the combined observations of the National Science Foundation's Very Large Array (VLA) and NASA's Chandra Observatory. The team's observations were able to use data on the jet to determine the spin axis of Sagittarius A*. This could help future astronomers determine how the Milky Way and its central black hole formed and evolved. The new paper has already determined that the object's spin is parallel to the rotation axis of the galaxy, suggesting that the Milky Way has not merged with any other galaxies in recent galactic history.
"We know this giant black hole has been much more active at consuming material in the past," said Frederick Baganoff, co-author of the paper and an astronomer at the Massachusetts Institute of Technology. "When it stirs again, the jet may brighten dramatically."
(Image courtesy NRAO/VLA/NASA/CXC/UCLA/Z. Li et al)