New Mid-sized Black Hole

Two types of black holes make up the majority of all black holes: supermassive black holes and stellar mass black holes. Mid-sized black holes exist as well, but they are harder to come by (only about half a dozen of them have been discovered).

Astronomers recently found evidence for the existence of another mid-sized black hole that is about 5000 times the mass of our sun. It is an ultraluminous X-ray source, which makes it one of the brightest X-ray sources in the universe. These astronomers also noticed flares in the vicinity of the black hole. One flashed at 27.6 times per minute, and the other one flashed at 17.4 times per minute, yielding a ratio of 3:2, which seems to be a common feature of both mid-sized black holes and stellar mass black holes.

Source: http://www.sciencedaily.com/releases/2015/09/150921095148.htm