SYDNEY, July 9 (UPI) -- Astronomers using an Australian radio telescope say they've confirmed the existence of the first known "middleweight" black hole.
Before the discovery of HLX-1, or "hyper-luminous X-ray source 1, in a galaxy about 300 million light-years from Earth, astronomers had good evidence for only supermassive black holes, a million to a billion times the mass of the Sun, and "stellar mass" ones, just three to 30 times the mass of the Sun.