The Hubble Space Telescope has detected a runaway supermassive black hole that they believe was kicked out from the galaxy core thanks to a huge directional emission of gravitational waves.
The dramatic scene is taking place in galaxy 3C186, located 8 billion light-years away. Its supermassive black hole, which weighs 1 billion times our Sun, is surprisingly not in the center of the galaxy, but appears to be moving out of the galaxy at a staggering speed of 7.5 million kilometers per hour (4.6 million mph). This extraordinary discovery has been reported in Astronomy & Astrophysics.
“We estimate that it took the equivalent energy of 100 million supernovae exploding simultaneously to jettison the black hole,” co-author Stefano Bianchi, from the Roma Tre University, said in a statement.
What could have produced such an incredible energy? The researchers are betting on gravitational waves. They suspect that the current supermassive black hole is the product of a black hole collision between two objects of different mass. This difference would have produced more gravitational waves in a certain direction at the moment of merging and that could have been the kick that propelled the black hole out of the center.
“If our theory is correct, the observations provide strong evidence that supermassive black holes can actually merge,” Bianchi added. “There is already evidence of black hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not yet completely understood.”
The discovery was possible because black holes begin feeding on stellar material as they move through galaxies. This object started a quasar phase, making it brighter than the rest of the galaxy. This was enough to pique the interest of astronomers.
“Black holes reside in the centers of galaxies, so it’s unusual to see a quasar not in the center,” added team leader Marco Chiaberge, ESA-AURA researcher at the Space Telescope Science Institute, USA.
The team hope to continue their investigation of this object with Hubble and other instruments like the Atacama Large Millimeter/submillimeter Array.