Dolores Beasley
Headquarters, Washington              Oct. 22, 2001
(Phone: 202/358-1753)

Bill Steigerwald
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-5017)

RELEASE: 01-200

NEW ENERGY SOURCE "WRINGS" POWER FROM BLACK HOLE SPIN

     Scientists for the first time have seen energy being 
extracted from a black hole. Like an electric dynamo, this 
black hole spins and pumps energy out through cable-like 
magnetic field lines into the chaotic gas whipping around it, 
making the gas -- already infernally hot from the sheer force 
of crushing gravity -- even hotter.

Joern Wilms of Tuebingen University, Germany, and an 
international team of astronomers observed the novel "power 
tapping" with the European Space Agency's X-ray Multi-Mirror 
Mission (XMM-Newton) satellite by watching a supermassive 
black hole in the core of galaxy named MCG-6-30-15. The 
observation also may explain the origin of particle jets in 
quasars. 

"Never before have we seen energy extracted from a black 
hole," said co-author Christopher Reynolds of the University 
of Maryland, College Park. "We always see energy going in, not 
out."

"The gravity in this region appears to be so intense that the 
very fabric of space twists around the black hole, dragging 
magnetic field lines along with it," said Wilms. "The magnetic 
fields tighten about the black hole, slowing its spin. This 
'friction' heats the region to even higher temperatures."

Scientists say most galaxies, including our Milky Way galaxy, 
have a supermassive black hole at their core. A supermassive 
black hole contains the mass of millions to billions of Suns 
compressed within a region smaller than our solar system. The 
black hole in MCG-6-30-15, over 100 million light-years from 
Earth, has the mass of about 100 million Suns.

The team observed the X-ray glow of iron gas traveling about 
half the speed of light very close to the black hole in MCG-6-
30-15's event horizon, the theoretical border of a black hole. 
XMM-Newton captured the spectrum, or chemical fingerprint, of 
this gas. The spectrum, laid out on a graph, resembles an 
electrocardiogram with its spikes and dips.

The iron spectrum from MCG-6-30-15 has extremely broad 
"spikes," an indication of gravity tugging at the particles of 
light, called photons, and literally stretching the light. MCG 
6-30-15's iron line was so broad, in fact, that the bulk of 
the light must emanate from very close to the black hole, 
where the force of gravity is the greatest, Reynolds said.

The total energy output, or luminosity indicated by the 
spectrum, however, was too bright to be powered by gravity and 
the free fall of matter alone. Some additional power source 
must exist to boost the luminosity to the observed intensity.

Co-author Mitchell Begelman of the University of Colorado, 
Boulder, said this finding may be observational evidence of a 
theory by Prof. Roger Blandford, currently at the California 
Institute of Technology, Pasadena, and Dr. Roman Znajek, when 
he was at Cambridge University in England, over 25 years ago. 
According to the theory, rotational energy can be extracted 
from the black hole as it is braked by magnetic fields. The 
first law of thermodynamics (conservation of energy) states 
that energy lost from the black hole must be absorbed by the 
region.

Begelman said the energy lost in MCG-6-30-15 is transferred to 
the inner edge of the accretion disk, a flow of gas swirling 
around and eventually falling into the black hole. The 
Blandford-Znajek theory implies that energy flows to particle 
jets emanating perpendicularly from the accretion disk in 
certain supermassive black hole systems called quasars. MCG 
6-30-15 is not a quasar, but Begelman said the theory can 
still apply because it predicts that the magnetic field might 
also link to the disk.

ASCA, a Japanese X-ray satellite, found possible evidence of a 
spinning black hole in 1994, but the signal was too weak to 
observe any evidence of energy being extracted from the black 
hole.

XMM-Newton, launched from French Guiana by ESA in December 
1999, carries three advanced X-ray telescopes with the light-
collecting ability to detect millions of sources, far greater 
than any previous X-ray mission. NASA helped fund mission 
development and supports guest observatory time. NASA's 
Goddard Space Flight Center, Greenbelt, Md., hosts the U.S. 
guest-observer support center.

Images are available at:
http://www.gsfc.nasa.gov/topstory/20011015blackhole.html
                            -end-
NOTE TO EDITORS: MCG-6-30-15 is written as MCG with a "minus 
sign" in front of the 6 but a "dash" in front of the 30 and 
15.