A “wandering” black hole more than 100,000 times the mass of the sun has been found on the outskirts of a galaxy about 4.5 billion light years from Earth.
Astronomers suspect that it was originally located at the center of a smaller galaxy, but was displaced during a collision with a larger one. The discovery gives credence to a long standing theory about the existence of wandering black holes.
Black holes – objects with such intense gravitational pull that nothing can escape from them, not even light – come in a range of sizes. Astronomers think that supermassive black holes (from 100,000 to 10 billion times the sun’s mass) or intermediate mass black holes (up to 100,000 times the mass of our sun) sit in the center of most galaxies.
However they can be ‘ejected’ from their position following a collision and merger with another galaxy containing a massive black hole, creating a “wandering” black hole.
A new study, published in The Astrophysical Journal, reports the discovery of one of these “wandering” black holes towards the edge of the lenticular galaxy GJ1417+52, which is about 4.5 billion light years from Earth.
Black holes themselves are not be visible, but astronomers can spot them by detecting the damage they do to their surroundings.
In this case, a star came too close to the black hole, named XJ1417+52, and was completely destroyed. This encounter generated a huge amount of X-rays, which were detected by NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton X-ray observatory.
Astronomers have previously spotted a few similar black holes but never anything on the scale of this latest discovery. Data showed XJ1417+52 about ten times brighter than the brightest X-ray source ever seen for a wandering black hole.
The extreme brightness of the object classifies it as a “hyper-luminous X-ray source,” and it features a mass about 100,000 times that of our sun.
The research team from the University of New Hampshire believe the black hole could have belonged to a smaller galaxy that crashed into GJ1417+52, stripping away most of the galaxy’s stars, leaving behind the black hole and its surrounding stars at the center of the galaxy.