But there is still much going on in M31. Two satellite galaxies, M32 and M110 (above and below M31 in this image) orbit M31 and perhaps have passed through it. A ring of relatively new star creation circles M31 and frames in blue its older, yellower core. If you look very closely in the blue of the ring, you may see patches of red or magenta, which are clouds of hydrogen emission nebulae and the places of current star formation. M31 is also ringed by clouds of dark dust; these represent star formation potential.
Two really fun things about this image: 1) M110 shows dust clouds near its center, one on each side of its core. 2) In the lower right, a very distant spiral galaxy shows through the arm of M31. It is not obvious in the large picture, so here is a close-up. I have no idea how far the galaxy is; pretty far, but I could not find a catalog designation in any of my maps, Nor could I find it marked on any of my maps. You can find it in this picture by its non-stellar shape and its dull color (which is similar to M31's core).
This image is RGB 24;28;16 x 900"; the data comes from DSW's FSQ.
