It was first cataloged as an interacting system VV 75, which is now considered (in NED) to be a single galaxy. Further, although KPG 265 is listed there as a "galaxy pair", KPG 265A is considered synonymous with NGC 3509 NED01, a "part of galaxy". I have noticed on other occasions that KPG seemed to inherit cases of complex but singular galactic morphology from the early VV. Arp simply called it "miscellaneous - large luminous system". It looks like a reasonably symmetric spiral to me (in photos), except that one arm is longer. The two compact knots are symmetrical with respect to the core, as such features commonly are in a spiral system. Good to know that, as Steve mentions, the explanation of the peculiar elements of its morphology can now be found in the interaction with the photographically far separated PGC edge-on to the NW.
Last edited by Ivan Maly; March 11th, 2014 at 02:03 PM.
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