The assumption that the characteristics of galaxies can be deduced by observing that the growth of the Milky Way and the mass of the black hole at its heart, are in parallel, will have to be revised. In Mayer’s model, the black hole grows much more quickly than the galaxy. It is therefore possible that the black hole is not regulated by the growth of the galaxy. It is far more possible that the galaxy is regulated by the growth of the black hole.
Mayer and his colleagues believe that their research will also be useful for physicists who search for gravitational waves and thus want to supply direct proof of Einstein’s theory of relativity. According to Einstein, who received his doctorate in 1906 at the University of Zurich, the merging of supermassive black holes must have caused massive gravitational waves – waves in a space-time continuum whose remains should still be measurable today.
More recently, using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA’s Chandra X-ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies.
By pointing Chandra at a patch of sky for more than six weeks, astronomers obtained what is known as the Chandra Deep Field South (CDFS). When combined with very deep optical and infrared images from NASA’s Hubble Space Telescope, the new Chandra data allowed astronomers to search for black holes in 200 distant galaxies, from when the universe was between about 800 million to 950 million years old.
“Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed,” said Ezequiel Treister of the University of Hawaii, lead author of the study appearing in the June 16 issue of the journal Nature. “Now we know they are there, and they are growing like gangbusters.”
The super-sized growth means that the black holes in the CDFS are less extreme versions of quasars — very luminous, rare objects powered by material falling onto supermassive black holes. However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.
The observations found that between 30 and 100 percent of the distant galaxies contain growing supermassive black holes. Extrapolating these results from the small observed field to the full sky, there are at least 30 million supermassive black holes in the early universe. This is a factor of 10,000 larger than the estimated number of quasars in the early universe.