Object name: ARP238
Arp 238/UGC 8335 is a pair of galaxies in northeastern Ursa Major about 425 million light-years distant. Arp put it in his category of galaxies with the appearance of fission. Just the opposite of what is likely really happening. His comment is apparently in error. He says: "Double nuclei, north nucleus has third arm." His image is oriented east up. Mine is north up. Hubble's image I've linked to is also east up. In the east up images, there is a third arm from the top (south) galaxy's core. Only 2 from the bottom (north) core. I wonder if Arp thought his image was north up when he made that comment. Normally he marks a V on the images' north side. In this case, the V is on the south side, likely leading to his error. Otherwise, I can't make sense out of it. I never could fathom his fission category either. These are merging not fissioning galaxies. That wasn't understood at his time it appears. He also had one for material ejected from nuclei. Later in life, he decided quasars were ejected from galaxies rather than the active nuclei of galaxies so far away only the accretion disk and possibly the jet from the core can be seen with the galaxy being lost in the glare. Today we have techniques to bring out the hidden galaxy that didn't exist in Arp's day. Still, his theories bordered on (some, would say "were" rather than "bordered on") quackery and got him kicked off the 200" telescope. I can't help but wonder if these categories, fission and ejection are related to this idea. Still, he was using appearance as his guide as no one knew for sure what was going on. His initial purpose for the atlas was to jump-start research into these peculiar galaxies in the hope it would lead to better understanding of how galaxies behave and evolve. He later used it to try and support his quasar ideas. Like Jerry Lewis, he was only appreciated in France. He lives there today last I knew. Edit: Since I wrote this he died December 28, 2013.