I was reading this article: Stirred, Not Shaken. Black Hole Antics Puff Up Whopper of a Galaxy.
Articles like this make me wonder whether the shape of a galaxy reflects the influences (gravity, spin, active/inactive) of the central black hole or lack thereof. Maybe a black hole with a mass and spin (moment of inertia) above a certain threshold causes a galaxy to become more spiral. Maybe if it spins with a wobble, the spiral develops a central bar. Maybe if the black hole has a moment of inertia that is below a certain threshold in proportion to the rest if the galaxy’s mass, the galaxy becomes elliptical.
Thoughts return to the weird relationship between the surface area of the black hole’s event horizon (not an existent, since “it” has no energy) to its entropy. Since entropy is a measure of information, the black hole behaves like a hologram. It again leads one to wonder whether the shape of the galaxy is a reflection of the information that is contained in the black hole.