Space Telescope Science
Astronomers have found an unlikely object in an improbable place: a monster black hole lurking inside one of the tiniest galaxies known. The dwarf galaxy containing the black hole is the densest galaxy ever seen, cramming 140 million stars within a diameter of about 300 light-years (just 1/500th of our Milky Way galaxy's diameter). However, the black hole inside the galaxy is five times the mass of the black hole at the center of our Milky Way. This suggests that the dwarf galaxy may actually be the stripped remnant of a larger galaxy that was torn apart during a close encounter with a more massive galaxy. The finding implies that there are many other compact galaxies in the universe that contain supermassive black holes.