Huge Black Hole Catapults Out of Own Galaxy

April 27th, 2008

For the first time in our history, astronomers have observed a colossal black hole being kicked out of its own galaxy. Scientists have theorized that it could happen, but have never witnessed such a phenomena before. Typically they suggest that the black holes of colliding galaxies tend to merge together, rather than being kicked out. Now they have witnessed the latter and released their results this week.

“We have observed the pre-merger stages of black holes,” said Stefanie Komossa of the Max Planck Institute for extraterrestrial Physics, part of the team that made the new discovery. “But we haven’t seen the actual merger event.”

Like anything else when it comes to this sort of phenomena there isn’t much to go on visually. Although astronomers have long believed that the black holes tend to merge, even that hasn’t been witnessed other than seeing the initial stages of such an event.

Komossa and her team have now detected the consequences of such a merger: a 100-million-solar mass black hole in the process of leaving its home galaxy.

“The consequence was that the merged black hole, the final product, the new black hole was expelled from the galaxy,” Komossa said. The team’s results are detailed in the May 10 issue of the journal Astrophysical Journal Letters. Certainly a discovery that will afford the team a set of new luxury watches,

The black holes may not merge right away though.

“One possibility is that for a long time they just orbit each other,” like binary stars, Komossa told SPACE.com.

Eventually, the orbiting black holes might interact with a star or surrounding gas which could cause them to lose angular momentum. “That would be a way to push them ever-closer towards each other,” Komossa said.

While reading about this event I saw a great video called Black Hole Diving. The video discusses the conditions that form black holes, as well as some discussion on how they track, and discover them.