Keep in mind that the outer spiral arms themselves may be very faint - so the galaxy may be wider than apparent (and thus, closer than apparent).
That would make it a very atypical galaxy, then. While galaxy cores are brighter than their arms, the arms are still full of stars, which have this habit of putting out lots of light. And having so sudden a drop-off in brightness as is depicted would be difficult to explain by known processes.
In the "canonverse" that thing might possibly be another object entirely - a star with some nebulosity, or something along those lines. Certainly that's how it's described in the TESB novel - as a big red star.
Excepting in how red it *isn't* in the movie scene. If you want to suggest something is a big, red star, it helps for it to be red. Making it blue-white, as seen in the image in the OP, doesn't say "big red star" to me at all.