Object name: ARP045
Arp 45 is two or three or four galaxies 400 million light-years distant in the northwest corner of Bootes. Arp put it in his category for spirals with low surface brightness companions on arms. Arp's comment: "One arm leads towards large companion, other towards small companion." Is this coincidence or is there some connection. There's another problem. Is the companion that is on the arm a galaxy as Arp indicates or just a blue knot in the arm? I don't know. UGC and Sloan, for instance, don't list it. Others such as the Vorontsov-Velyaminov Interacting Galaxies catalog as well as the CGCG and MCG list it separately. I find no redshift measurement for it. In the UGC catalog, Arp 45 is 09178. It is a triple galaxy in that catalog but the third member is not the blue knot on the arm. It is somewhat to the northwest, a normal looking disk galaxy, a bit smaller the primary galaxy of Arp 45. While an obvious spiral NED shows no classification for it. The main spiral of Arp 45 is classed S(B?)c. I thought it a rather obvious barred spiral so I don't understand the question mark. The companion, VV2b, is close to being a one-armed spiral though NED doesn't attempt to classify it. The blue object on the other arm of VV2a has neither a magnitude nor classification at NED.