At left, is a three-filter (uvw1, uvm2 and uvw2) ultraviolet image of Messier 81, a spiral galaxy 12 million light-years away in the Ursa Major constellation. At right is a visible image from the Sloan Digital Sky Survey. M81’s companion galaxy, Holmberg IX, is barely visible in the optical, but its young stars shine brightly in the ultraviolet.
Swift carries three instruments for detailed observations of gamma ray bursts. The X-ray Telescope (XRT) and the UV/Optical Telescope (UVOT) were built by Penn State, Leicester University and the Mullard Space Science Laboratory (both in England) and at the Osservatorio Astronomico di Brera (in Italy). The third instrument is the Burst Alert Telescope (BAT). Swift was launched into a low-Earth orbit on a Delta 7320 rocket on November 20, 2004.