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This artist's conception of the 4C60.07 system shows two colliding galaxies, one of which (left) has already turned most of its gas into stars and its black hole is ejecting jets of charged particles. This galaxy is pulling gas and dust from the neighboring galaxy (right), where star formation is occurring. Credit: David A. Hardy/UK ATC |
Our Milky Way galaxy contains a supermassive black hole at its core, as do most if not all other large galaxies in the modern universe. These gravity wells can have masses of millions to billions times that of the sun.
Now, astronomers have more support for the idea that such black holes are common among the earliest galaxies going back to nearly the beginning of time. A new study suggests galactic black holes were around even 12 billion years ago when the universe was only 1.7 billion years old and galaxies were just beginning to form, the astronomers said.
The new conclusion comes from the discovery of two distant and interacting galaxies, both of which contain black holes at their hearts that will most likely merge. The pair is 12 billion light-years away, which means the light seen by astronomers left the scene 12 billion years ago. (A light-year is the distance light will travel in a year, or about 6 trillion miles, or 10 trillion km.)
"Remarkably, both galaxies contain supermassive black holes at their centers, each capable of powering a billion, billion, billion light bulbs," said lead researcher Rob Ivison of the United Kingdom Astronomy Technology Center. "The implications are wide-reaching: You can't help wondering how many other colossal black holes may be lurking unseen in the distant universe."
Astronomers had first noticed one of the galaxies, called 4C60.07, due to its bright radio emission, which is a telltale sign of a quasar, or a rapidly spinning black hole that is feeding on its home galaxy. And until now, they thought hydrogen gas surrounding the central black hole was undergoing a burst of star formation, churning out stellar babies at a rate of about 5,000 suns every year.
More recently, they used the Submillimeter Array of eight radio antennas located in Hawaii, finding 4C60.07 was not forming stars after all. In fact, its stars appeared to be relatively old and quiescent.
Instead, a burst of star formation is taking place in the previously unseen companion galaxy, which is rich in gas and deeply enshrouded in dust. The new radio emission data also showed a stream of gas being pulled from this newly discovered galaxy by its neighbor, 4C60.07.
"These two galaxies are fraternal twins," said researcher Steve Willner of the Harvard-Smithsonian Center for Astrophysics in Massachusetts. "Both are about the size of the Milky Way, but each one is unique."
The research also involved looking at data on the galaxies collected by the Spitzer Space Telescope.?
"The expectation is that the galaxies would merge and then the black holes would merge," Willner told SPACE.com. "And I don't want to be anywhere nearby when that happens. It'll be very spectacular."
He added, "By now, if we could see them now probably we would have a very big, but old galaxy with one giant black hole in the center that's the merger of the two."
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