False-color image of the most distant black hole currently known. In addition to the bright central black hole (white), the image shows the surrounding host galaxy (red).
Credit: Tomotsugu GOTO, University of Hawaii
SYDNEY: Astronomers have found a supermassive black hole so far away it’s almost as old as the universe itself. It may provide new clues to investigate the evolution of galaxies.
The huge galaxy that surrounds the black hole is similar in size to the Milky Way, but is so distant that the light we see from it is 12.8 billion years old.
"It is surprising that such a giant galaxy existed when the universe was only one-sixteenth of its present age,” said lead-author Tomotsugu Goto, of the University of Hawaii in Honolulu. “The galaxy and black hole must have formed very rapidly in the early universe."
Billion times the Sun's mass
The black hole is huge, with at least a billion times as much matter as our Sun, said the researchers. The findings are published in the September edition of the Monthly Notices of the Royal Astronomical Society.
When matter is sucked into the gravitational pull of a black hole, it swirls around at great speeds and pressures – like water down a plughole – and creates a ‘quasar’. These are among the brightest objects in the universe.
Even though no light escapes from black holes themselves, quasars allow astronomers to detect them. However, because quasars are so bright, they blind us to the dimmer light coming from the galaxies that surround them, and until recently have prevented us from studying them.
Subtracting the light
Now, using the improved sensitivity of the University of Hawaii’s Subaru telescope and a clever mathematical model, which cancels out the bright light of the quasar, Goto's team have been able to study the galaxy that surrounds it.
This is important, because by examining the black hole and the host galaxy, experts may be able to study how they evolved together.
"We have witnessed a supermassive black hole and its host galaxy forming together,” said astronomer and co-author Yousuke Utsumi of the National Astronomical Observatory in Tokyo, Japan. “This discovery has opened a new window for investigating galaxy-black hole co-evolution at the dawn of the universe."
