Celestial hemisphere:  Southern  ·  Constellation: Aquarius (Aqr)  ·  Contains:  NGC 7252
Getting plate-solving status, please wait...
Arp 226 - NGC 7252, Gary Imm
Arp 226 - NGC 7252, Gary Imm

Arp 226 - NGC 7252

Getting plate-solving status, please wait...
Arp 226 - NGC 7252, Gary Imm
Arp 226 - NGC 7252, Gary Imm

Arp 226 - NGC 7252

Equipment

Loading...

Acquisition details

Loading...

Description

This is a beautifully disturbed galaxy located 220 million light years away in the southern constellation of Aquarius, at a declination of -25 degrees. This is a huge galaxy - 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. I don't like giving such a unique and wonderful object a silly nickname, so I am not going to call it that.

This galaxy is classified as an elliptical galaxy, which is somewhat misleading. The Hubble image of this galaxy 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 if this is a merger of two equal galaxies, why is the inner disk so pristine and seemingly unaffected? Scientists believe that this spiral disk was formed as a result of the merger, but it also seems reasonable that the spiral disk may simply be a remnant of the original galaxy.

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 down and right 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.

In addition to the subject galaxy, numerous galaxies and galaxy clusters are visible in the background.

Comments

Revisions

  • Arp 226 - NGC 7252, Gary Imm
    Original
  • Arp 226 - NGC 7252, Gary Imm
    E

E

Description: Comparison to Original Arp Image

Uploaded: ...

Sky plot

Sky plot

Histogram

Arp 226 - NGC 7252, Gary Imm