Interesting faint arm or tidal stream feature encircling this one like a halo. Looking at DSS data to see the surrounding sky, I don't see any obvious interaction partners. I suppose this is a late stage of some kind of interaction, and all galaxies involved have now merged. I wonder if some kind of small, diffuse galaxy could interact in such a way that it got pulled around nearly into a circle like this. If that were the case, then this would be more of a middle stage than an end stage. Anyway, that's just a lot of speculation.
I was interrupted in the middle of processing this by a rather large earthquake.
All Channels: ACS/WFC F606W
North is 6.4° counter-clockwise from up.