Observations hint at a new recipe for giant black holes | Science | AAAS
http://www.sciencemag.org/news/2017/01/observations-hint-new-recipe-giant-black-holes
Here's a thought experiment that has unsettled astrophysicists: Start the clock at the beginning of time. Form a black hole in the usual way,
through the collapse of a massive star. To make it grow, force-feed it with gas, which will resist being devoured by heating up and dispersing
as it nears the black hole's maw. Try to grow a black hole fast enough to explain the ones that existed in the real universe when it was just
a billion years old: monsters a billion times the mass of the sun that drive the powerful beacons called quasars.
"It's very difficult," says Amy Reines, an observational astronomer at the National Optical Astronomy Observatory in Tucson, Arizona. Astronomer
Nico Cappelluti of Yale University is more definitive. "There is no way to grow such a massive black hole from an ordinary stellar black hole,"
he says. But he and others see hints of a faster route involving primordial gas clouds, as they described last week at the winter meeting of
the American Astronomical Society in Grapevine, Texas.
