I am full of admiration for Wolfgang Ries and Stefan Heutz for producing such a fine portrait of a fascinating interacting pair of galaxies that more than 300 million light-years from the Earth. As if that wasn't enough, two moderately bright stars - 9th and 10th magnitude - complicate matters by lining up right next to the faint 13th magnitude galaxies.
So you did extremely well, Wolfgang and Stefan!
Arp 273. NASA/ESA and Hubble Space Telescope.
Arp 272. NASA, ESA, the Hubble Heritage (STScI/AURA)
ESA/Hubble Collaboration, and K. Noll (STScI)
For all of that, today's APOD can't compete with the Hubble portrait of the same galaxies, and I don't see how it could be otherwise.
The Hubble portrait of Arp 273 (the picture at left) shows a fascinating detail in the larger galaxy. At 1 o'clock, there is what looks like a tiny barred galaxy tangled in the large spiral's outer arm. Colorwise, the small barred object is non-red enough to be at the same general distance as Arp 273. Personally I believe that this object really is a small intruder, and that it has affected the large galaxy's structure. Note the numerous large and small blue clusters that seem to emanate from the general vicinity of the small trespasser and flow left, until they merge with the long, sweeping arm of the large galaxy. Similar clusters are found in a shorter arm of the large galaxy as well, an arm that seems to point directly at the intruder.
An even more striking example of a very small galaxy entering the "battle" between two larger galaxies is Arp 272, the galaxy pair at right. You can't miss the small galaxy that seems to sit smack in the middle of an "overhead arm" joining NGC 6050 and IC 1179.
I'd like to add, speaking of today's APOD, that Wolfgang Ries and Stefan Heutz' image sheds light on the Hubble portrait bringing out the colors of NGC 273 in a way that is really illuminating. You can see the small intruder as a tiny orange dot in today's APOD, and you can also see a long line of strikingly blue clusters in the vicinity of the intruder. The very regular arms of the large galaxy suggests that they are affected more by tidal forces than by the ravages of runaway star formation, but the color gradient of the arms still let us see clearly what parts of the arm are forming new stars and what parts aren't.
Ann