File:Atoms for Peace Galaxy.png

This is a close-up of NGC 7252, which is also called the <a href="http://en.wikipedia.org/wiki/NGC_7252" rel="nofollow">Atoms for Peace Galaxy</a>. Chaotic streams of stars encircle the galaxy and two much longer arms extend into widefield images of the galaxy but are cut off in this one. Clearly, a lot of rearrangement of stars is going on, here. It's obvious that a collision has taken place but it's not at all obvious how the shells form which you can see as concentric rings encircling the nucleus. There are a lot of other examples of shells in the archive but due to visual interest and aesthetics they will never be as well known by the public as majestic spiral galaxies.

I combined a rather strange set of data to create this image. The chip gap had to be filled with cloned data for the green channel but not for the blue or red so this is two parts Frankenstein and one part hack job. Red represents three combined bandpasses of infrared, green is actually blue light and blue is ultraviolet and blue light.

The data I used came from these two proposals: <a href="http://archive.stsci.edu/proposal_search.php?mission=hst&id=11554" rel="nofollow">Luminosity Profiles of Extremely Massive Clusters in NGC 7252</a> <a href="http://archive.stsci.edu/proposal_search.php?mission=hst&id=11691" rel="nofollow">Using Massive Star Clusters in Merger Remnants To Provide Reference Colors of Intermediate-Age Stellar Populations</a>

Red: hst_11554_02_wfc3_uvis_f775w_sci + WFC3/IR IR F110W + WFC3/IR IR F160W Green: hst_11554_01_wfc3_uvis_f475w_sci Blue: hst_11691_02_wfc3_uvis_f336w_sci + hst_11554_01_wfc3_uvis_f475w_sci