4/14/2015

Mysterious galaxy cluster looks like a cosmic finger painting

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The region Abell 2256 shown as it would appear to human eyes if we could see radio waves.NRAO
When galaxies collide, the results can be particularly spectacular from a distant vantage point. The above is a "true color" radio image from the Very Large Array in a remote stretch of New Mexico showing a region called Abell 2256 about 800 million light-years away -- an area 4 million light-years across where hundreds of galaxies are colliding.

The result is a variety of mysterious phenomena that can be observed only by looking at the radio waves emitted from the area rather than visible light waves. Basically, the image takes the rainbow of hues we're used to seeing and uses them to represent different lengths of radio waves, so the reds in the image represent longer radio waves, while blue indicates shorter radio waves and the other colors represent the ones in between. You can see an example of what the visible light show from a different galactic collision looks like here.
Some of the features resemble the nebula-like shapes we're used to seeing following a supernova explosion, but there are plenty of other odd shapes that look like flaws in the imaging process, except that they are not. There are no stray hairs, fingerprints or smudges in this radio image. Instead, astronomers refer to the shapes by equally colorful names such as "Large Relic," "Halo" and "Long Tail."
"The image reveals details of the interactions between the two merging [galaxy] clusters and suggests that previously unexpected physical processes are at work in such encounters," Frazer Owen of the National Radio Astronomy Observatory said in a statement.