The other two galaxies barely register in the UV. NGC 470 shows up strongly in the GALEX UV images which suggests that there is a lot of star formation going on in it. NGC 470 has some very chunky spiral arms and there are some suggestions of plumes in deep images.
It is not clear if NGC 470 is gravitationally interacting with NGC 474 as well. It would appear that NGC 474 ingested a spiral galaxy in two phases, the first pass being about 1.3 billion years ago and the final pass about 900,000 million years ago. Shell galaxies come about when another galaxy has been digested and the stars thrown out from the interaction form these shells. Shell galaxies are relatively rare, with maybe 10-20% of galaxies in this class, so to get two in the same field is unusual. NGC 467 is also suggested to be a lenticular galaxy. NGC 467 is also a shell galaxy but is much further away than the others, although some older sources do suggest it is gravitationally part of the NGC 474 group. The pair lie at about 100 million light-years from us. It is not clear whether Arp meant Arp 227 to include both NGC 470 and NGC 474, or just NGC 474.Īrp 227 is a shell galaxy and appears to be in a physical pair with NGC 470. NGC 474 is also a disturbed system and Arp included it as Arp 227. NGC 470 is a disturbed system and was included by Vorontosv-Velyaminov as number 948 in his extended catalogue. NGC 470 and NGC 474 in 1784 and then NGC 467 a year later in 1785. All three galaxies were found by William Herschel. The triplet includes NGC 467, NGC 470 and NGC 474. I must thank Mark Stuart for recommending this group to me. Our galaxy of the month this month is the tight triplet of galaxies in Pisces around NGC 470. Sorry the image isn't interactive, but you don't have javascript enabled. We also have a finder chart that should help you locate these galaxies, as will this link for NGC 470 on the Stellarium Web planetarium. This interactive image of the NGC 470 was provided by the Pan-STARRS1 Surveys using Aladin Sky Atlas.
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