Andrew Yee[_1_]
January 10th 08, 01:00 AM
Jennifer Morcone
Marshall Space Flight Center, Huntsville, Ala.
256-544-7199
Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998
For Release: January 09, 2008
Jet Power and Black Hole Assortment Revealed in New Chandra Image
A dramatic new Chandra image of the nearby galaxy Centaurus A provides one
of the best views to date of the effects of an active supermassive black
hole. Opposing jets of high-energy particles can be seen extending to the
outer reaches of the galaxy, and numerous smaller black holes in binary star
systems are also visible.
The image was made from an ultra-deep look at the galaxy Centaurus A,
equivalent to more than seven days of continuous observations. Centaurus A
is the nearest galaxy to Earth that contains a supermassive black hole
actively powering a jet.
A prominent X-ray jet extending for 13,000 light years points to the upper
left in the image, with a shorter "counterjet" aimed in the opposite
direction. Astronomers think that such jets are important vehicles for
transporting energy from the black hole to the much larger dimensions of a
galaxy, and affecting the rate at which stars form there.
High-energy electrons spiraling around magnetic field lines produce the
X-ray emission from the jet and counterjet. This emission quickly saps the
energy from the electrons, so they must be continually reaccelerated or the
X-rays will fade out. Knot-like features in the jets detected in the Chandra
image show where the acceleration of particles to high energies is currently
occurring, and provides important clues to understanding the process that
accelerates the electrons to near-light speeds.
The inner part of the X-ray jet close to the black hole is dominated by
these knots of X-ray emission, which probably come from shock waves -- akin
to sonic booms -- caused by the jet. Farther from the black hole there is
more diffuse X-ray emission in the jet. The cause of particle acceleration
in this part of the jet is unknown.
Hundreds of point-like sources are also seen in the Chandra image. Many of
these are X-ray binaries that contain a stellar-mass black hole and a
companion star in orbit around one another. Determining the population and
properties of these black holes should help scientists better understand the
evolution of massive stars and the formation of black holes.
Another surprise was the detection of two particularly bright X-ray
binaries. These sources may contain stellar mass black holes that are
unusually massive, and this Chandra observation might have caught them
gobbling up material at a high rate.
In this image, low-energy X-rays are colored red, intermediate-energy X-rays
are green, and the highest-energy X-rays detected by Chandra are blue. The
dark green and blue bands running almost perpendicular to the jet are dust
lanes that absorb X-rays. This dust lane was created when Centaurus A merged
with another galaxy perhaps 100 million years ago.
This research was presented at the American Astronomical Society meeting on
January 9th by Gregory Sivakoff (The Ohio State University). Other team
members include Ralph Kraft (Harvard-Smithsonian Center for Astrophysics),
Martin Hardcastle (University of Hertfordshire), Diana Worrall (University
of Bristol), and Andres Jordan (Smithsonian Astrophysical Observatory).
NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra
program for the agency's Science Mission Directorate. The Smithsonian
Astrophysical Observatory controls science and flight operations from the
Chandra X-ray Center in Cambridge, Mass.
Additional information and images are available at:
http://chandra.harvard.edu/photo/2008/cena/
and
http://chandra.nasa.gov
Marshall Space Flight Center, Huntsville, Ala.
256-544-7199
Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
617-496-7998
For Release: January 09, 2008
Jet Power and Black Hole Assortment Revealed in New Chandra Image
A dramatic new Chandra image of the nearby galaxy Centaurus A provides one
of the best views to date of the effects of an active supermassive black
hole. Opposing jets of high-energy particles can be seen extending to the
outer reaches of the galaxy, and numerous smaller black holes in binary star
systems are also visible.
The image was made from an ultra-deep look at the galaxy Centaurus A,
equivalent to more than seven days of continuous observations. Centaurus A
is the nearest galaxy to Earth that contains a supermassive black hole
actively powering a jet.
A prominent X-ray jet extending for 13,000 light years points to the upper
left in the image, with a shorter "counterjet" aimed in the opposite
direction. Astronomers think that such jets are important vehicles for
transporting energy from the black hole to the much larger dimensions of a
galaxy, and affecting the rate at which stars form there.
High-energy electrons spiraling around magnetic field lines produce the
X-ray emission from the jet and counterjet. This emission quickly saps the
energy from the electrons, so they must be continually reaccelerated or the
X-rays will fade out. Knot-like features in the jets detected in the Chandra
image show where the acceleration of particles to high energies is currently
occurring, and provides important clues to understanding the process that
accelerates the electrons to near-light speeds.
The inner part of the X-ray jet close to the black hole is dominated by
these knots of X-ray emission, which probably come from shock waves -- akin
to sonic booms -- caused by the jet. Farther from the black hole there is
more diffuse X-ray emission in the jet. The cause of particle acceleration
in this part of the jet is unknown.
Hundreds of point-like sources are also seen in the Chandra image. Many of
these are X-ray binaries that contain a stellar-mass black hole and a
companion star in orbit around one another. Determining the population and
properties of these black holes should help scientists better understand the
evolution of massive stars and the formation of black holes.
Another surprise was the detection of two particularly bright X-ray
binaries. These sources may contain stellar mass black holes that are
unusually massive, and this Chandra observation might have caught them
gobbling up material at a high rate.
In this image, low-energy X-rays are colored red, intermediate-energy X-rays
are green, and the highest-energy X-rays detected by Chandra are blue. The
dark green and blue bands running almost perpendicular to the jet are dust
lanes that absorb X-rays. This dust lane was created when Centaurus A merged
with another galaxy perhaps 100 million years ago.
This research was presented at the American Astronomical Society meeting on
January 9th by Gregory Sivakoff (The Ohio State University). Other team
members include Ralph Kraft (Harvard-Smithsonian Center for Astrophysics),
Martin Hardcastle (University of Hertfordshire), Diana Worrall (University
of Bristol), and Andres Jordan (Smithsonian Astrophysical Observatory).
NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra
program for the agency's Science Mission Directorate. The Smithsonian
Astrophysical Observatory controls science and flight operations from the
Chandra X-ray Center in Cambridge, Mass.
Additional information and images are available at:
http://chandra.harvard.edu/photo/2008/cena/
and
http://chandra.nasa.gov