Makes astronomers think they need to rethink theory on black hole formation
Space news (Black hole formation theory) – 200 million light-years from Earth in the direction of the constellation Eridanus –
Astronomers working on current black hole formation theory have detected a supermassive black hole at the center of a galaxy in a region of space and time they didn’t expect to find such a monster. A very hungry monster containing the mass of over 17 billion suns, residing in an out-of-the-way galactic backwater town.
Previously, astronomers detected titanic supermassive black holes at the center of huge, very massive galaxies in parts of space and time with a greater density of large galaxies. The very crowded Coma galaxy cluster has over 1,000 galaxies and is home to the biggest monster supermassive black hole recorded with an estimated mass of 21 billion times that of Sol.
“The newly discovered supersized black hole resides in the center of a massive elliptical galaxy, NGC 1600, located in a cosmic backwater, a small grouping of 20 or so galaxies,” said lead discoverer Chung-Pei Ma, a University of California-Berkeley astronomer and head of the MASSIVE Survey, a study of the most massive galaxies and supermassive black holes in the local universe. “While finding a gigantic black hole in a massive galaxy in a crowded area of the universe is to be expected – like running across a skyscraper in Manhattan – it seemed less likely they could be found in the universe’s small towns.”
“There are quite a few galaxies the size of NGC 1600 that reside in average-size galaxy groups,” Ma said. “We estimate that these smaller groups are about 50 times more abundant than spectacular galaxy clusters like the Coma cluster. So the question now is, ‘Is this the tip of an iceberg?’ Maybe there are more monster black holes out there that don’t live in a skyscraper in Manhattan, but in a tall building somewhere in the Midwestern plains.”
Astrophysicists studying NGC 1600 detected a supermassive black hole at least ten times more massive than current theory predicted at its center. Scientists previously thought the more massive the central bulge of a galaxy, proportionally more massive the supermassive black hole at its center should be, but this throws a wrench in previous correlations between the mass of a supermassive black hole and its central bulge of suns.
“It appears that that relation does not work very well with extremely massive black holes; they are a larger fraction of the host galaxy’s mass,” Ma said.
What could cause this smaller galaxy in a cosmic backwater to have such a titanic supermassive black hole at its core? It could be NGC 1600 merged with another galaxy hundreds of millions of years ago when such collisions were more common in this region of spacetime. Computer simulations show the central supermassive black holes of two merging galaxies fall into the center of the recently formed galaxy and begin orbiting each other in a slowly diminishing radius. Stars and other stellar objects that fall into the core steal momentum from the twirling monsters and in the process are often flung from the center of the galaxy. This transfer of momentum causes the supermassive black holes to slowly move closer together and eventually merge to form a super monster. A super monster that continues to grow by devouring gas drawn into the center of the galaxy by collisions and gravity.
In the words of Ma, “To become this massive, the black hole would have had a very voracious phase during which it devoured lots of gas.”
Astronomers continue to watch
Is it possible constant merging of NGC 1600 with galactic neighbors is one reason it lives in a cosmic backwater, with relatively few nearby galactic neighbors? It’s the brightest galaxy in town, more than three times brighter than any member of its galactic group. This difference in brightness has rarely been observed in other galactic groups. Maybe lots of galactic mergers resulted in one of the most titanic supermassive black holes ever recorded, residing in a small, cosmic backwater town.
The super monster lurking at the center of NGC 1600 is currently sleeping, but astronomers are watching for signs of its next meal going down. While they wait, they’re working on updating current theory on the formation of black holes, using the data obtained by studying NGC 1600 and similar galaxies. Current theory that will likely need to be revamped once new data comes in during our journey to the beginning of space and time.
The tide of science may rise and fall, but it always seeks truth in the facts.
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