Astronomers report that they have discovered the most gigantic black holes ever found in the universe, an abyss 10 times the size of our solar system, encompassing regions or "event horizons" about five times the distance from the sun to Pluto or about 2,500 times as massive as the black hole at the center of the Milky Way.
The biggest of of these monsters, which weighs as much as 21 billion Suns, is in an egg-shaped galaxy known as NGC 4889, the brightest galaxy in the Coma cluster of thousands of galaxies about 335 million light-years away. The image at bottom of page shows the central region of the Coma cluster, with giant elliptical galaxies NGC 4889 and NGC 4874.
"These two black holes are significantly more massive than predicted," the astronomers wrote.
They said their calculations suggest that different evolutionary processes influence the growth of the largest galaxies and their black holes than in smaller galaxies. Astronomers have long suspected that since the universe began it has harboured black holes with a mass the size of the two newly found giants.
Chung-Pei Ma, led a team of University of California, Berkeley astronomers who used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas and outer space to weigh the black holes in the centers of galaxies by clocking the speeds of stars orbiting around them; the faster the stars are going, the more gravity — and thus mass — is needed to keep the stars from flying away. They report their work in the journal Nature, which will be published online on Wednesday.
These cosmic gluttons grow in tandem with their galaxies, slurping up gases, planets and stars.
"There is a symbiotic relationship between black holes and their galaxies that has existed since the dawn of time," Kevin Schawinski, a Yale astronomer said in a June study.
Martin Rees, a cosmologist at Cambridge University, called the new work “an incremental step,” noting that the study of these monsters has been a part of his life for a long time. “It’s good to learn about even bigger ones,” he said.
One question astronomers would like answered is how these black holes got so big, billions of times bigger than a typical dead star. Dr. Ma described it as a kind of nature-versus-nurture argument, explaining that black holes could grow by merging with other black holes as galaxies merge to get bigger — “nature” — or by swallowing gas around them — “nurture.”
“Our discovery of extremely massive black holes in the largest present-day galaxies suggests that these galaxies could be the ancient remains of voracious ancestors," said McConnell. Astronomers think the supermassive black holes in galaxies could be the missing link between the quasars of early universe that were powered by giant black holes in gargantuan feeding frenzies, spewing massive amounts of energy into space.