Fischer and Tully discovered that they obey a velocity-luminosity relation similar to the Faber-Jackson law for ellipticals.
Their namesake features can be described with the density-wave theory developed by Lin and Shu. In 1920, before telescopes capable of resolving these objects were developed, Shapley and Curtis debated their nature. Fischer and Tully discovered that they obey a velocity-luminosity relation similar to the Faber-Jackson law for ellipticals. In about one-third, the arms extend from a bar-shaped center. The Whirlpool, Andromeda, and Milky Way are all examples of, FTP, what type of galaxy named for its shape?
Their namesake features can be described with the density-wave theory developed by Lin and Shu.
spiral galaxy (accept barred spiral galaxy before "bar-shaped center")