A monster black hole has been flung from its home galaxy and is careening through space, according to a new study.
Astronomers spotted the supermassive black hole – the type usually found lurking in the center of galaxies – hightailing it out of a distant galaxy at considerable speed. The cosmic ejection is taking place more than half a billion light-years from Earth. The discovery was made with archived observations from the Chandra X-ray Observatory.
Though black holes themselves don't shine, the material they gobble up heats as it falls in and releases radiation in the form of X-ray light. Normally these bright X-ray spots are seen in the centers of galaxies, but in this case, researchers found one offset to the side.
The kicked-out black hole could result from a special set of circumstances, according to computer simulations.
Supermassive black holes can contain the mass of more than a billion suns. Just how they accumulate all that mass is unknown, but some astronomers think they form when two smaller black holes collide.
Depending on the direction and speed with which the two black holes rotate before they merge, the resulting gigantor may be thrown out of the galaxy, resulting in the cosmic interloper spotted in the Chandra observations.
Studying such recoiling black holes could provide more clues about how supermassive black holes form.
Undergraduate student Marianne Heida of the University of Utrecht in The Netherlands spotted the rogue black hole monster while poring through the Chandra Source Catalog – a listing of bright X-ray sources in the sky made by the orbiting observatory.
Heida, who worked on a project at the SRON Netherlands Institute for Space Research, compared these X-ray spots with the known positions of millions of galaxies to map out the locations of supermassive black holes.
This oddball black hole may be just the first of many similar discoveries to come, the researchers said.
"We have found many more objects in this strange class of X-ray sources," Heida said. "With Chandra we should be able to make the accurate measurements we need to pinpoint them more precisely and identify their nature."
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