Scientists catch supermassive black hole in spin mode
For the first time ever, astrophysicists have observed extra energy escaping from the supermassive black hole at the center of a distant galaxy.
Undertaken with the European Space Agency's XMM Newton satellite and an international team of researchers, the study indicates that he black hole is spinning, emitting energy through a tangled web of magnetic field lines into the super-hot gases whirling slightly more slowly around it.
The gas then becomes even hotter.
"The magnetic field lines are like a series of cable-like strands twisted and tightened around the black hole by intense gravity," said chief study author Jörn Wilms of the University of Tübingen in Germany.
"Our results indicate the X-ray emissions from gas connected to the magnetic field lines are much stronger and much closer to the black hole than we expected."
A paper on the subject is to be published in the Monthly Notices of the Royal Astronomical Society in London.
"What's really new here is evidence of additional energy coming from the spin of the black hole," said a co-author of the paper, Prof. Mitchell Begelman of the astrophysical and planetary sciences department of the University of Colorado at Boulder. "The web of magnetic field is imposed on the black hole from the gases around it, slowing its spin."
Begelman likened the magnetic field to a truck clutch being let out to slow the vehicle's speed while traveling downhill.
Black holes are collapsed objects so tightly compacted that not even light can escape their gravitational pull.
Although scientists at NASA's Goddard Space Flight Center showed recently that small black holes believed to pepper the universe can spin, this is the first evidence that supermassive black holes can, too.
The supermassive black hole that Wilms, Begelman, and colleagues studied is known as MCG -6-30-15. It lies more than 100 million light-years from Earth.
Begelman likened the black hole to a giant battery, storing huge amounts of energy from the constant stream of gas clouds and the occasional stars it gulps up.
"It would take roughly a billion years to release all the energy stored up in MCG-6-30-15," he said.
Understanding how fast a supermassive black hole is spinning may be an accurate and sensitive probe of how black holes are formed, said Begelman.
If one is spinning relatively slowly, it probably has been growing gradually by absorbing individual clouds of gas, stars, and much smaller, ordinary black holes formed by single-star collapses. "But if it is spinning rapidly, it suggests to us that supermassive black holes were formed in a single catastrophic event, perhaps associated with the formation of a galaxy," Begelman said.