Proto supermassive binary black hole detected in X-rays (Forwarded)

Journal Astronomy & Astrophysics
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Contact persons:

Science:

Dr. Daniel Hudson
Phone: +49 228 73 6788

Dr. Thomas Reiprich
Phone: +49 228 73 3642

Dr. Craig L. Sarazin
Phone: +1 434 924 4903

Dr. Tracy E. Clarke
Email: tracy.clarke (at) nrl.navy.mil

Press office:

Dr. Jennifer Martin
Journal Astronomy & Astrophysics
Phone: +33 1 43 29 05 41

Press Release: April 6th, 2006

This press release is issued as a collaboration with the University of
Bonn, the University of Virginia, the U.S. Naval Research Laboratory,
the Chandra X-ray Observatory Center , and Astronomy & Astrophysics.

Proto supermassive binary black hole detected in X-rays

An international team of astronomers led by D. Hudson from the
University of Bonn has detected a proto supermassive binary black hole
in images of NASA's Chandra X-ray observatory. They found that these two
black holes are gravitationally bound and orbit each other. Their
results will be published in an upcoming issue of Astronomy & Astrophysics.

An international team of astrophysicists, led by D. Hudson from the
University of Bonn and including the U.S. Naval Research Laboratory and
the University of Virginia, presents their X-ray detection of a proto
supermassive binary black hole. Their results will be published in an
upcoming issue of Astronomy & Astrophysics. The image of this proto
binary black hole was obtained with NASA's Chandra X-ray Observatory.
The two black holes have already been seen in radio images. The new
X-ray images provide unique evidence that these two black holes are in
the process of forming a binary system; that is, they are
gravitationally bound and orbit each other.

The two black holes are located in the nearby galaxy cluster Abell 400.
With high-resolution Chandra data, the team was able to spatially
resolve the two supermassive black holes (separated by 15") at the
centre of the cluster. Each black hole is located at the centre of its
respective host galaxy and the host galaxies appear to be merging. It is
not, however, just the two host galaxies that are colliding -- the whole
cluster in which they live is merging into another neighbouring galaxy
cluster.

Using these new data, the team show that the two black holes are moving
through the intracluster medium at the supersonic speed of about 1200
km/s. The wind from such a motion would cause the radio plasma emitted
from these two black holes to bend backwards. Although this bending had
been observed previously, the cause of it was still being debated. Since
the bending of the jets due to this motion is in the same direction, it
suggests that the two black holes are travelling along the same path
within the cluster and are therefore gravitationally bound.

These two black holes became gravitationally bound when their host
galaxies collided. In several million years, the two black holes will
probably coalesce causing a burst of gravitational waves, as predicted
by Einstein's theory of relativity. This event will produce one of the
brightest sources of gravitational radiation in the Universe. Although
we will not be around to see this particular one, the observations
provide additional evidence that such bound systems exist and are
currently merging. The gravitational waves produced by these mergers are
believed to be the biggest source of gravitational waves to be detected
by the future Laser Interferometer Space Antenna (LISA).

The team includes D.S. Hudson (AIfA,Germany), T.H. Reiprich
(AIfA,Germany), T.E. Clarke (NRL & Interferometrics Inc.,USA), and C.L.
Sarazin (UVa,USA).

X-ray detection of the proto supermassive binary black hole at the
centre of Abell 400
by D.S Hudson, T.H. Reiprich, T.E. Clarke, and C.L. Sarazin.
To be published in Astronomy & Astrophysics (DOI number:
10.1051/0004-6361:20064955)

Full article available in PDF format,

http://www.edpsciences.org/articles/...PRAA200608.pdf

IMAGE CAPTION:
[http://www.edpsciences.org/papers/aa...608/pr_fig.gif
(76KB)]
This image shows the central region of the galaxy cluster Abell 400. The
colour coding gives the temperature of the X-ray emitting gas trapped in
the cluster: black-cold (18 million degrees Celsius) to white-hot (38
million degrees Celsius). The contours show the radio emission from the
jets of plasma being expelled by the black holes. As the two black holes
stream through the gas at supersonic velocities, the jets are bent
toward the top of the image. The gas in front of the black holes is
compressed and heated, as seen by the hotspot below them.

The inset shows a blow up of the central regions. Each dot represents a
position where an X-ray photon has struck Chandra's X-ray camera. The
two black holes are seen as bright regions where as many as 250 X-ray
photons struck the camera. The contours again show the radio emission
from the black holes and the jets of plasma being ejected from them.

[NOTE: Additional images are available at
http://chandra.harvard.edu/photo/2006/a400/ ]

"Andrew Yee" ""ayee \"@ nova.astro.utoronto.ca" wrote in message
.. .
An international team of astronomers led by D. Hudson from the University
of Bonn has detected a proto supermassive binary black hole in images of
NASA's Chandra X-ray observatory.

Umm, they didn't find them out in space somewhere? Sorry. I couldn't
resist.

George