Researchers used the National Aeronautics and Space Administration's Chandra
X-ray Observatory to study nine supermassive black holes at the centers of elliptical
galaxies to reach their findings.
The black holes, which were .2 to three billion times the mass of the sun,
are relatively old and generate much less radiation than quasars, the fast growing
black holes seen in the early universe.
The researchers said the Chandra findings show that most of the energy released
by matter falling toward a supermassive black hole is in the form of high-energy
jets travelling at near the speed of light away from a black hole.
"Just as with cars, it's critical to know the fuel efficiency of black holes," said
lead author Steve Allen of the Kavli Institute for Particle Astrophysics and
Cosmology at Stanford University and the Stanford Linear Accelerator Center.
The researchers believe their work could be crucial to understanding how
the high-energy jets can be launched from magnetized disks of gas near the black
hole's event horizon, the distance from a black hole within which nothing, even
light, can escape.
The authors said they were surprised to discover that the black holes are
all producing much more energy in jets of high-energy particles than in visible
light or X-rays.
Some of the gas first drawn to the black holes may be blown away by the energetic
activity before it gets too close to a black hole, but a significant amount
must eventually approach the event horizon, where it is used with high efficiency
to power the jets, the authors said.
Their findings will be published in the upcoming issue of the Monthly Notices
of the Royal Astronomical Society.
