sombrero galaxy (also known as messier object 104, m104 or ngc 4594) is an unbarred spiral galaxy in the constellation virgo located 31 million light-years (9.5 mpc)2 from earth. the galaxy has a diameter of approximately 50.000 light-years, 30% the size of the milky way. it has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk. the dark dust lane and the bulge give this galaxy the appearance of a sombrero. astronomers initially thought that the halo was small and light, indicative of a spiral galaxy, but spitzer found that the halo around the sombrero galaxy is larger and more massive than previously thought, indicative of a giant elliptical galaxy.3 the galaxy has an apparent magnitude of +9.0, making it easily visible with amateur telescopes, and it is considered by some authors to be the brightest galaxy within a radius of 10 megaparsecs of the milky way. its large bulge, its central supermassive black hole, and its dust lane all attract the attention of professional astronomers.