Maunakea, Hawaii – An international team of astrophysicists led by Benny Trakhtenbrot, a researcher at ETH Zurich’s Institute for Astronomy, discovered a gigantic black hole in an otherwise normal galaxy, using W. M. Keck Observatory’s 10-meter, Keck I telescope in Hawaii. The team, conducting a fairly routine hunt for ancient, massive black holes, was surprised to find one with a mass of more than 7 billion times our Sun making it among the most massive black holes ever discovered. And because the galaxy it was discovered in was fairly typical in size, the study calls into question previous assumptions on the development of galaxies. Their findings are being published today in the journal Science.
Even more surprising than the black hole’s record mass, was the relatively ordinary mass of the galaxy that contained it.
Until now, observations have indicated that the greater the number of stars present in the host galaxy, the bigger the black hole. “This is true for the local Universe, which merely reflects the situation in the Universe’s recent past,” Urry said.
The latest results, however, suggest that these processes work differently, at least in the early Universe.
The distant young black hole observed by Trakhtenbrot, Urry and their colleagues had roughly 10 times less mass than its galaxy. In today’s local Universe, black holes typically reach a mass of 0.2 to 0.5 percent of their host galaxy’s mass. “That means this black hole grew much more efficiently than its galaxy – contradicting the models that predicted a hand-in-hand development,” he said.
Institute for Astronomy, Switzerland
W. M. Keck Observatory