Astronomers using the Karl G. Jansky Very Large Array (VLA) and the
Chandra X-Ray Observatory have produced a spectacular image revealing
new details of violent collisions involving at least four clusters of
galaxies. Combined with an earlier image from NASA's Hubble Space
Telescope (HST), the new observations show a complex region more than 5
billion light-years from Earth where the collisions are triggering a
host of phenomena that scientists still are working to understand.
The
HST image forms the background of this composite, with the X-ray
emission detected by Chandra in blue and radio emission seen by the VLA
in red. The X-rays indicate hot, tenuous gas that pervades the region
containing the galaxy clusters. The large, oddly-shaped red feature at
the center probably is a region where shocks caused by the collisions
are accelerating particles that then interact with magnetic fields and
emit the radio waves.
"The complex shape of this region is
unique; we've never spotted anything like this before," said Reinout van
Weeren, an Einstein Fellow at the Harvard-Smithsonian Center for
Astrophysics. "The shape probably is the result of the multiple ongoing
collisions," he added.
The new radio and X-ray observations are
much more sensitive than previous ones, the scientists said. The
combination of these images will make this region one of the
best-studied examples of cluster-cluster collisions yet known, and can
yield new insights on the complex interactions during cluster mergers.
Together, the merging clusters are called MACS J0717+3745, which also is
one of the HST Frontier Fields for which HST will produce the deepest
observations ever. The scientists presented their findings to the
American Astronomical Society's meeting in Boston, Mass.
The
straight, elongated radio-emitting object is a foreground galaxy whose
central black hole is accelerating jets of particles in two directions.
The red object at bottom-left is a radio galaxy that probably is falling
into the cluster.
Contact:
Dave Finley, Public Information Officer
(575) 835-7302
email: dfinley@nrao.edu
The National Radio Astronomy Observatory (NRAO) is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
