Black hole threesome: Supermassive trio are 'rippling' space

Black hole threesome: Supermassive trio are 'rippling' space
Close-pair binary and their mate
By Brid-Aine Parnell, 26 Jun 2014



The closely circling black holes are in a galaxy more than four billion light years away and are the tightest trio ever spotted by scientists. Finding three supermassive black holes together is not that unusual, but the discovery of this lot indicates that the situation may be even more common than previously thought.

Galaxies often form from mergers of other star systems, so for a galazy to end up with more than one supermassive black hole at its heart is not uncommon. Boffins currently know of four triple systems, but the closest pairs in those systems are around 7,825 light-years apart.

In the system affectionately and tongue-twistingly known as SDSS J150243.09+111557.3, the closest black holes are so near to each other, researchers originally the pair of them were one hole.

However, using the European VLBI Network, a group of astroboffins figured out that there were really three of the huge black holes, with two of them just 455 light years away from each other. That makes them the second-closest pair of supermassive black holes ever known.

More:
http://www.theregister.co.uk/2014/06/26/trio_of_supermassive_black_holes_found/