... Its very remarkable behavior stems from a compact object, a black hole or neutron star, which has produced an accretion disk with jets. ... In this 1994 photograph by the Hubble Space Telescope, a disk of hot gas was found to be orbiting at the center of this massive elliptical galaxy. ... Uranus' Largest Moon: Titania . ... X-ray Moon and X-ray Star . ... An X-ray star winks out behind the Moon in these before and after views of a lunar occultation of the galactic X-ray source designated GX5-1. ...