Composite image of Abell 2744 region, with radio, X-Ray, and optical (visible light) data combined.
Credit: Pearce et al.; Bill Saxton, NRAO/AUI/NSF; Chandra, Subaru; ESO. Hi-res image
Radio-only image of Abell 2744 region, showing radio-emitting features caused by subatomic particles accelerated to high speeds by the collisions of giant clusters of galaxies. Credit: Pearce et al., NRAO/AUI/NS. Hi-res image
Animated GIF cycles through the individual images (radio, X-ray, optical) of Abell 2744.
Credit: Pearce et al.; Bill Saxton, NRAO/AUI/NSF; Chandra; Subaru; ESO. Hi-res image
A giant collision of several galaxy clusters, each containing
hundreds of galaxies, has produced this spectacular panorama of shocks
and energy. The collisions generated shock waves that set off a
celestial fireworks display of bright radio emission, seen as red and
orange. In the center of the image, the purple indicates X-rays caused
by extreme heating.
The region is collectively known as Abell 2744, some 4 billion
light-years from Earth. The radio portion of the image comes from new
observations made with the National Science Foundation’s Karl G. Jansky
Very Large Array (VLA), and is combined with earlier data from NASA’s
Chandra X-ray observatory. Both are overlaid on an image at
visible-light wavelengths made with data from the Subaru telescope and
the Very Large Telescope (VLT). The new VLA observations revealed
previously undetected regions where shocks accelerated subatomic
particles, causing radio emission.
Astronomers are studying the combined image in an attempt to decipher
the sequence of galaxy-cluster collisions. Currently, they said,
evidence indicates a North-South (top-bottom in the image) collision of
subclusters and an East-West (left-right in the image) collision. There
is a possible third collision, and the astronomers continue to analyze
their data to uncover more details about the region’s complex history of
collisions and their aftermath.
The scientists reported their findings in a paper in the Astrophysical Journal
by Connor Pearce, of the Harvard-Smithsonian Center for Astrophysics
and the University of Southampton in the UK, and an international team
of colleagues.
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