http://www.space.com/23755-black-hole-brightness-mystery.html
November 27, 2013 - Space.com
A black-hole system in a neighboring galaxy is twice as bright as astronomers had thought possible, a new study reports.
The incredible luminosity of the system in question, which resides
about 22 million light-years from Earth in the Pinwheel Galaxy, may
force a rethink of the theories that explain how some black holes radiate energy, researchers said.
...
The research team, led by Jifeng Liu of the Chinese Academy of Sciences
in Beijing, studied ULX-1 using the Gemini Observatory in Hawaii and two
NASA spacecraft, the Hubble Space Telescope and the Chandra X-ray Observatory.
...