... Black Hole Candidate Cygnus X 1 . ... The Cygnus X-1 binary star system contains one of the best candidates for a black hole . The system was discovered because it is one of the brightest X-ray sources on the sky, shining so bright it was detected by the earliest rockets carrying cameras capable of seeing the previously unknown X-ray sky . ... Publications with keywords: X-ray - black hole - Cyg X-1 . Publications with words: X-ray - black hole - Cyg X-1 . ... M81: Feeding a Black Hole . ...