Celestial hemisphere:  Southern  ·  Constellation: Aquarius (Aqr)  ·  Contains:  NGC 7252
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Arp 226, Gary Imm
Arp 226, Gary Imm

Arp 226

Getting plate-solving status, please wait...
Arp 226, Gary Imm
Arp 226, Gary Imm

Arp 226

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Description

This object, also known as NGC 7252, is a beautifully disturbed galaxy located 220 million light years away in the southern constellation of Aquarius, at a declination of -25 degrees. The object is huge - the inner region has an apparent diameter of almost 2 arc-minutes which corresponds to a diameter of 120,000 light years, while the outer regions extend to a mind boggling 400,000 light years.

The amazing flowing, helically twisting star streams are the highlight. This object has been given the nickname "Atoms for Peace", due to its resemblance to an atomic nucleus. It is also the same name as the title of a speech given by President Eisenhower in 1953.

This galaxy is classified as an elliptical galaxy, which doesn't seem quite right based upon the Hubble image seen in the mouseover.  It would be more correct to say that this object is on its way to becoming an elliptical galaxy.

The Hubble image is fantastic in its detail and puts my image to shame.  My only consolation is that, unlike the Hubble, my wider FOV allowed me to capture the extent of the star streams.

The Hubble image shows that the bright small 0.4 arc-minute diameter inner disk surrounding the core has the structure of a spiral galaxy with dust lanes. My setup is not able to capture these details and it only shows up as a bright area around the core. It is commonly believed that this object is the result of the merger of two relatively equal sized galaxies but I am not so sure. Certainly the magnificent star streams are evidence of gravitation interaction, but it seems to me that this object is more like our Milky Way - a galaxy whose surrounding star streams are due to smaller satellite galaxies which are slowly being integrated into the large host. 

The Hubble image also shows that the bright arcing bands seen in the middle region of the object are bright bluish star clusters, signs of extensive star formation kicked off by the gravitational interaction. Note the bright region which looks like a band extending up and left from the core. This region was studied in 2013 in a paper by Schweizer et al entitled, "The OIII Nebula of the Merger Remnant NGC 7252: A Likely Faint Ionization Echo". In the paper, this bright region is identified as a "Voorwerp" (Dutch for "small object"), similar to but smaller than the first Voorwerp, "Hanny's Voorwerp" near IC 2497, discovered in 2007. This is a new category of sky object which is a faint ionization echo comprised of glowing oxygen gas. I did not image this object in narrowband yet to confirm its presence.

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